ARM: 6879/1: fix personality test wrt usage of domain handlers

There are optional bits that may complement a personality ID.  It is
therefore wrong to simply test against the absolute current->personality
value to determine the effective personality.  The PER_LINUX_32BIT is
itself just PER_LINUX with one of those optional bits set.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>