[SPARC]: Deal with glibc changing macro names in modpost.c

GLIBC 2.3.4 and later changed the STT_REGISTER macro to
STT_SPARC_REGISTER, so we need to cope with that somehow.

Original patch from fabbione, reposted by Ben Collins.

Signed-off-by: David S. Miller <davem@davemloft.net>