clocksource/drivers/at91: Fix IO endianness

clocksource/drivers/at91: Fix IO endianness

Fix the use of __raw IO accessor with the readl/writel_relaxed()
versions to allow the code to be used on a system running in big
endian mode.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Andrew Victor <linux@maxim.org.za>
Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>
Cc: Linux ARM Kernel <linux-arm-kernel@lists.infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: digetx@gmail.com
Cc: hdegoede@redhat.com
Cc: laurent.pinchart+renesas@ideasonboard.com
Cc: maxime.ripard@free-electrons.com
Cc: viresh.kumar@linaro.org
Link: http://lkml.kernel.org/r/1427746633-9137-7-git-send-email-daniel.lezcano@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>