arch: riscv: update ARCH_STACK_PTR_ALIGN on RV32E to 4 bytes fails testing at nrf54l15 cpuflpr

[nordic-piks]

Describe the bug
The tests:
~ 200 tests are affected.
example:
zephyr/tests/drivers/timer/nrf_grtc_timer

Observed for

• nrf54l15pdk/nrf54l15/cpuflpr

To Reproduce
Steps to reproduce the behavior:

1. have nrf54l15pdk/nrf54l15/cpuflpr connected
2. go to your zephyr dir
3. west build -b nrf54l15pdk/nrf54l15/cpuflpr --sysbuild -- -DSB_CONFIG_VPR_LAUNCHER=y
4. west flash --skip-rebuild --erase
5. See console output

Expected behavior
Valid console output but there is no console output at all.

Impact
Not clear

Environment (please complete the following information):

• OS: Ubuntu 20.04.1 LTS
• Toolchain Zephyr SDK 0.16.8
• Commit SHA or Version used: v3.7.0-829-g15aab68d29d9

[nordic-piks]

I did bisect and found that #76791 cause this problem. FYI @ycsin
FYI @masz-nordic @gmarull

[ycsin]

Probably I misunderstood the meaning of ARCH_STACK_PTR_ALIGN? I've created #77047 that should fix this issue and also keep the #76762 fixed