kbuild: update ARCH alias info for sh

In Kbuild documentation, add alias for 64-bit sh ARCH ("sh64")
to the list of ARCH aliases.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
1 file changed