mender-uboot: Reduce SPL size to fit in Scarthgap

It seems the uboot image in Scarthgap has grown such that the default
autoconfig setup for at least Beaglebone no longer fits in sram:

   cp u-boot-dtb.bin u-boot.bin
|    rm -f spl/drivers/mtd/nand/built-in.o; arm-poky-linux-gnueabi-ar cDPrsT spl/drivers/mtd/nand/built-in.o spl/drivers/mtd/nand/raw/built-in.o
|    rm -f spl/drivers/mtd/built-in.o; arm-poky-linux-gnueabi-ar cDPrsT spl/drivers/mtd/built-in.o spl/drivers/mtd/mtd.o spl/drivers/mtd/nand/built-in.o
|    rm -f spl/drivers/built-in.o; arm-poky-linux-gnueabi-ar cDPrsT spl/drivers/built-in.o spl/drivers/block/built-in.o spl/drivers/core/built-in.o spl/drivers/gpio/built-in.o spl/drivers/i2c/built-in.o spl/drivers/mmc/built-in.o spl/drivers/mtd/built-in.o spl/drivers/net/built-in.o spl/drivers/power/built-in.o spl/drivers/serial/built-in.o spl/drivers/bus/built-in.o spl/drivers/usb/musb-new/built-in.o spl/drivers/usb/gadget/built-in.o spl/drivers/usb/common/built-in.o spl/drivers/usb/gadget/udc/built-in.o spl/drivers/watchdog/built-in.o spl/drivers/soc/built-in.o
|   ( cd spl && arm-poky-linux-gnueabi-ld.bfd -z noexecstack --no-warn-rwx-segments -T u-boot-spl.lds --gc-sections -Bstatic --gc-sections  --no-dynamic-linker --build-id=none -Ttext 0x402F0400 arch/arm/cpu/armv7/start.o --whole-archive arch/arm/mach-omap2/built-in.o arch/arm/cpu/armv7/built-in.o arch/arm/cpu/built-in.o arch/arm/lib/built-in.o board/ti/am335x/built-in.o board/ti/common/built-in.o common/spl/built-in.o common/init/built-in.o boot/built-in.o common/built-in.o cmd/built-in.o env/built-in.o lib/built-in.o disk/built-in.o drivers/built-in.o drivers/usb/dwc3/built-in.o drivers/usb/cdns3/built-in.o dts/built-in.o fs/built-in.o net/built-in.o  --no-whole-archive arch/arm/lib/eabi_compat.o arch/arm/lib/lib.a -Map u-boot-spl.map -o u-boot-spl )
| arm-poky-linux-gnueabi-ld.bfd: u-boot-spl section `__u_boot_list' will not fit in region `.sram'
| arm-poky-linux-gnueabi-ld.bfd: region `.sram' overflowed by 824 bytes
| make[2]: *** [/work/dmoseley/scratch/mender-beaglebone/build/tmp/work/beaglebone_yocto-poky-linux-gnueabi/u-boot/2024.01/git/scripts/Makefile.spl:527: spl/u-boot-spl] Error 1
| make[1]: *** [/work/dmoseley/scratch/mender-beaglebone/build/tmp/work/beaglebone_yocto-poky-linux-gnueabi/u-boot/2024.01/git/Makefile:2054: spl/u-boot-spl] Error 2

This patch removes a few USB config options from SPL which should not be needed
in a Mender config since it is just going to load the main uboot image from SDCard.

Signed-off-by: Drew Moseley <drew@moseleynet.net>
Changelog: Title
Ticket: None

meta-mender-beaglebone/recipes-bsp/u-boot/files/#reduce-spl-size.cfg#

@@ -0,0 +1,4 @@
+# CONFIG_SPL_USB_GADGET is not set
+# CONFIG_SPL_USB_ETHER is not set
+# CONFIG_SPL_USB_ETH_RNDIS is not set
+# CONFIG_SPL_MUSB_NEW is not set

meta-mender-beaglebone/recipes-bsp/u-boot/files/.#reduce-spl-size.cfg

@@ -0,0 +1 @@
+dmoseley@aruba.home.moseleynet.net.47795:1720727731

meta-mender-beaglebone/recipes-bsp/u-boot/files/reduce-spl-size.cfg

@@ -0,0 +1,4 @@
+# CONFIG_SPL_USB_GADGET is not set
+# CONFIG_SPL_USB_ETHER is not set
+# CONFIG_SPL_USB_ETH_RNDIS is not set
+# CONFIG_SPL_MUSB_NEW is not set

meta-mender-beaglebone/recipes-bsp/u-boot/u-boot_%.bbappend

@@ -1,2 +1,8 @@
+FILESEXTRAPATHS:prepend := "${THISDIR}/files:"
+
+SRC_URI:append:mender-uboot = " file://reduce-spl-size.cfg "
+
 MENDER_UBOOT_PRE_SETUP_COMMANDS:beaglebone-yocto = "run findfdt; setenv mender_dtb_name \${fdtfile}"
 MENDER_UBOOT_PRE_SETUP_COMMANDS:append:beaglebone-yocto:mender-uboot = "; setenv bootargs \${bootargs} rootwait"
+
+