[ARM] 3849/1: fix get_unaligned() for gcc >= 4.1

gcc 4.1's __typeof__ propagates 'const', which breaks get_unaligned().
Rewrite get_unaligned() not to use __typeof__.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>