[PATCH] x86_64: Eliminate IA32_NR_syscalls define

Or rather compute it based on the table length automatically.

This also has the intended side effect of not warning for new system calls
anymore.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>