x86, syscall: Re-fix typo in comment

Fix the same typo as was fixed in:

b7641d2c x86-64, syscall: Adjust comment spacing and remove typo

... for the new versions of this file (32-bit and IA32 compat).

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Link: http://lkml.kernel.org/r/1321569446-20433-4-git-send-email-hpa@linux.intel.com