Reinitialize RT CDI to an HMAC of a buffer of 0s in disable attestation

[sree-revoori1]

This is necessary so that we can use the RT CDI to generate a DICE key. We cannot simply erase a key vault slot and then reuse it.

fixes #932

[jhand2]

Looks good. Could you also update the PR description once this has been tested with the FPGA? (Just running the test_disable_attestation_cmd test should be sufficient)

[zhalvorsen]

warm_reset_basic and test_disable_attestation both passed when run on an FPGA.

$ CPTRA_UIO_NUM=4 cargo nextest run --no-fail-fast --features=fpga_realtime,itrng -E 'test(warm_reset_basic)'
   Compiling caliptra-error v0.1.0 (/home/ubuntu/caliptra-sw/error)-fail-fast --features=fpga_realtime,itrng -E 'test(warm_reset_basic
   Compiling dpe v0.1.0 (/home/ubuntu/caliptra-sw/dpe/dpe)
   Compiling caliptra-image-types v0.1.0 (/home/ubuntu/caliptra-sw/image/types)
   Compiling caliptra-image-gen v0.1.0 (/home/ubuntu/caliptra-sw/image/gen)
   Compiling caliptra-rom v0.1.0 (/home/ubuntu/caliptra-sw/rom/dev)
   Compiling caliptra-image-openssl v0.1.0 (/home/ubuntu/caliptra-sw/image/openssl)
   Compiling caliptra-image-elf v0.1.0 (/home/ubuntu/caliptra-sw/image/elf)
   Compiling caliptra-image-fake-keys v0.1.0 (/home/ubuntu/caliptra-sw/image/fake-keys)
   Compiling caliptra-image-serde v0.1.0 (/home/ubuntu/caliptra-sw/image/serde)
   Compiling caliptra-builder v0.1.0 (/home/ubuntu/caliptra-sw/builder)
   Compiling caliptra-drivers v0.1.0 (/home/ubuntu/caliptra-sw/drivers)
   Compiling caliptra-size-history v0.1.0 (/home/ubuntu/caliptra-sw/ci-tools/size-history)
   Compiling caliptra-image-verify v0.1.0 (/home/ubuntu/caliptra-sw/image/verify)
   Compiling caliptra_common v0.1.0 (/home/ubuntu/caliptra-sw/common)
   Compiling caliptra-emu-cpu v0.1.0 (/home/ubuntu/caliptra-sw/sw-emulator/lib/cpu)
   Compiling caliptra-cpu v0.1.0 (/home/ubuntu/caliptra-sw/cpu)
   Compiling caliptra-gen-linker-scripts v0.1.0 (/home/ubuntu/caliptra-sw/cpu/gen)
   Compiling caliptra-kat v0.1.0 (/home/ubuntu/caliptra-sw/kat)
   Compiling caliptra-cfi-lib v0.1.0 (/home/ubuntu/caliptra-sw/cfi/lib)
   Compiling caliptra-emu-periph v0.1.0 (/home/ubuntu/caliptra-sw/sw-emulator/lib/periph)
   Compiling caliptra-x509 v0.1.0 (/home/ubuntu/caliptra-sw/x509)
   Compiling caliptra-runtime v0.1.0 (/home/ubuntu/caliptra-sw/runtime)
   Compiling caliptra-fmc v0.1.0 (/home/ubuntu/caliptra-sw/fmc)
   Compiling caliptra-test-harness v0.1.0 (/home/ubuntu/caliptra-sw/test-harness)
   Compiling caliptra-drivers-test-bin v0.1.0 (/home/ubuntu/caliptra-sw/drivers/test-fw)
   Compiling caliptra-image-app v0.5.0 (/home/ubuntu/caliptra-sw/image/app)
   Compiling caliptra-hw-model v0.1.0 (/home/ubuntu/caliptra-sw/hw-model)
   Compiling caliptra-test v0.1.0 (/home/ubuntu/caliptra-sw/test)
   Compiling caliptra-rom-test-fmc v0.1.0 (/home/ubuntu/caliptra-sw/rom/dev/tools/test-fmc)
   Compiling caliptra-fmc-mock-rt v0.1.0 (/home/ubuntu/caliptra-sw/fmc/test-fw/test-rt)
   Compiling compliance-test v0.1.0 (/home/ubuntu/caliptra-sw/sw-emulator/compliance-test)
   Compiling caliptra-rom-test-rt v0.1.0 (/home/ubuntu/caliptra-sw/rom/dev/tools/test-rt)
   Compiling caliptra-hw-model-c-binding v0.1.0 (/home/ubuntu/caliptra-sw/hw-model/c-binding)
   Compiling vector_gen v0.1.0 (/home/ubuntu/caliptra-sw/drivers/test-fw/scripts/vector_gen)
   Compiling caliptra-emu v0.1.0 (/home/ubuntu/caliptra-sw/sw-emulator/app)
   Compiling caliptra-file-header-fix v0.1.0 (/home/ubuntu/caliptra-sw/ci-tools/file-header-fix)
    Finished test [unoptimized + debuginfo] target(s) in 11m 17s
    Starting 1 test across 84 binaries (1207 skipped)
        SLOW [> 60.000s] caliptra-test::warm_reset warm_reset_basic
        PASS [ 112.742s] caliptra-test::warm_reset warm_reset_basic
------------                                                                                                                                                                                                                                                       
     Summary [ 112.755s] 1 test run: 1 passed (1 slow), 1207 skipped 

$ CPTRA_UIO_NUM=4 cargo nextest run --no-fail-fast --features=fpga_realtime,itrng -E 'test(test_disable_attestation)'

    Finished test [unoptimized + debuginfo] target(s) in 1.24s
    Starting 1 test across 84 binaries (1207 skipped)
        PASS [  23.462s] caliptra-runtime::integration_tests test_disable_attestation_cmd
------------
     Summary [  23.475s] 1 test run: 1 passed, 1207 skipped