x86/compat: Remove compat_ni_syscall()

compat_ni_syscall() does the same thing as sys_ni_syscall().

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1425439896-8322-2-git-send-email-brgerst@gmail.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>