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>

# Dummy config file to not use a C library *at all*

## depends on BARE_METAL

##

## help Do not use a C library.

## help

## help This is usefull if your project is self-contained, does not rely on

## help an external C library, and provides all the necessary bits.

## help

## help Most probably usefull to bootloaders, as they generally don't depend

## help on the C library.

## help

## help If unsure: do *not* choose that, and use another option in the choice.