This removes the need to select ARCH_ARM in SOC Kconfig
Also don't define the default as this result in spurious lines in the
.config.
Change-Id: I1ed4a71599641db606510e5304b9f0acf9b7eb88
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31313
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>