arm: config: Introduce CONFIG_SYS_ARM_ARCH

arm: config: Introduce CONFIG_SYS_ARM_ARCH

Introduce new helper Kconfig option, which is automatically set to
the version of ARM architecture for which the U-Boot is built. This
is useful when selecting tuning options in the libgcc imported from
Linux kernel.

Signed-off-by: Marek Vasut <[email protected]>
Cc: Albert Aribaud <[email protected]>
Cc: Masahiro Yamada <[email protected]>
Cc: Simon Glass <[email protected]>
Cc: Tom Rini <[email protected]>
Reviewed-by: Tom Rini <[email protected]>