x32: Fix stupid ia32/x32 inversion in the siginfo format

Fix a stray ! which flipped the sense if we were generating a signal
frame for ia32 vs. x32.

Introduced in:

e7084fd5 x32: Switch to a 64-bit clock_t

Reported-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Gregory M. Lueck <gregory.m.lueck@intel.com>
Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com