ARM: 7616/1: cache-l2x0: aurora: Use writel_relaxed instead of writel

The use of writel instead of writel_relaxed lead to deadlock in some
situation (SMP on Armada 370 for instance). The use of writel_relaxed
as it was done in the rest of this driver fixes this bug.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>