[SPARC]: Clean up asm-sparc/elf.h pollution in userspace.

We don't need to export sparc_elf_hwcap() to userspace, and it doesn't
build there.  Remove it by moving it inside #ifdef __KERNEL__, along with
some other things which don't need to be exported.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>