arm64: setup: report ELF_PLATFORM as the machine for utsname
arm64: setup: report ELF_PLATFORM as the machine for utsname

uname -m reports the machine field from the current utsname, which should
reflect the endianness of the system.

This patch reports ELF_PLATFORM for the field, so that everything appears
consistent from userspace.

Signed-off-by: Will Deacon <b913f13ef92ac157955c954ccaaff7be065faba4@arm.com>
Signed-off-by: Catalin Marinas <15ce75b290ebaf27c3f9fd73ab848685ed3d8261@arm.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs