kernel/linux: prepare for arch whose kenel name is not the standard name

For some architectures, the kernel architecture name is not the common
name of the architecture for other tools.

For example: ARM 64-bit is commonly referenced as aarch64, but the kernel
calls it arm64.

Signed-off-by: Michael Hope <michael.hope@linaro.org>
Signed-off-by: Zhenqiang Chen <zhenqiang.chen@linaro.org>
[yann.morin.1998@free.fr: split out of the aarch64 patch]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

# SPARC specific config options

## select ARCH_SUPPORTS_32

## select ARCH_SUPPORTS_64

## select ARCH_DEFAULT_32

## select ARCH_USE_MMU

## select ARCH_SUPPORTS_WITH_CPU

## select ARCH_SUPPORTS_WITH_TUNE

## select ARCH_SUPPORTS_WITH_FLOAT

##

## help The SUN SPARC architecture, as defined by:

## help     32 bit: http://www.sparc.org/standards/V8.pdf

## help     64 bit: http://www.sparc.org/standards/SPARCV9.pdf