ARM: 6473/1: Small update to ux500 specific L2 cache code

This change updates the ux500 specific outer cache code to use
the new *_relaxed() I/O accessors.

Signed-off-by: Per Fransson <per.xx.fransson@stericsson.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>