Pass down the correct EXTRA_CFLAGS to the compiler driver when building
assembler source.
Otherwise building busybox for a multilib other than the default failed
to link since hash_md5_sha256_x86-64_shaNI.o and
hash_md5_sha_x86-64_shaNI.o were built for the default arch which might
not what we requested in the EXTRA_CFLAGS.
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
831c754c91