ARM: 7542/1: mm: fix cache LoUIS API for xscale and feroceon

Some architectures like xscale and feroceon have cache API variants that
map cache flushing functions as aliases to the base architecture.
This patch adds the required aliases to complete the implementation of
cache flushing LoUIS API.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>