linux-phytec-ti

x86-64, ia32: Move compat_ni_syscall into C and its own file

Move compat_ni_syscall out of ia32entry.S and into its own .c file.
Although this is a trivial function, it is not performance-critical,
and this will simplify further cleanups.

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