[ARM] 3234/1: Update cpu_architecture() to deal with the new ID format

Patch from Catalin Marinas

Since ARM1176, the CPU ID format has changed and it will also be used for
future ARM architectures.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>