x86, asmlinkage: Make various syscalls asmlinkage

FWIW I suspect sys_rt_sigreturn/sys_sigreturn should use
standard SYSCALL wrappers.  But I didn't do that change in this
patch.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375740170-7446-7-git-send-email-andi@firstfloor.org


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>