[ARM] 3741/1: remove sa1111.c build warning on non-sa1100 systems

Patch from David Brownell

Remove buld warning when building sa1111 on non-sa1100 platforms (e.g. PXA).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>