[PATCH] x86_64: fix bug in csum_partial_copy_generic()

I was observing reproducible crashes on the "movw %bx,(%rsi)" instruction
below while a process in a recvfrom() system call was copying packet data
to user space.  The patch below fixes the exception table and causes the
crash to no longer reproduce.  Please apply.

Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>