[SPARC32]: Silence sparc32 warnings on missing syscalls.

Silence sparc32 warnings on missing syscalls, these won't be added.
This patch is based on this mail:
http://www.mail-archive.com/linux-arch@vger.kernel.org/msg02571.html

Signed-off-by: Martin Habets <errandir_news@mph.eclipse.co.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>