x86, xsave: Make init_xstate_buf static

The pointer is only used in xsave.c. Making it static.

Signed-off-by: Robert Richter <robert.richter@amd.com>
LKML-Reference: <1279731838-1522-5-git-send-email-robert.richter@amd.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>