[ARM] 3373/1: move uengine loader to arch/arm/common

Patch from Lennert Buytenhek

Move the uengine loader from arch/arm/mach-ixp2000 to arch/arm/common
so that ixp23xx can use it too.

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