x86, x32, audit: Fix x32's AUDIT_ARCH wrt audit

is_compat_task() is the wrong check for audit arch; the check should
be is_ia32_task(): x32 syscalls should be AUDIT_ARCH_X86_64, not
AUDIT_ARCH_I386.

CONFIG_AUDITSYSCALL is currently incompatible with x32, so this has
no visible effect.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/a0138ed8c709882aec06e4acc30bfa9b623b8717.1409954077.git.luto@amacapital.net


Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>