ARM: EXYNOS: Fixups for big-endian operation

If the kernel is built big endian, then using the __raw read and write IO
accessors is not going to work as they end up writing big-endian data to
little-endian IO registers. Fix this by using the readl and writel relaxed
versions which ensure little endian IO.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>