ARM: EXYNOS4: Divorce mct from local timer API

Separate the mct local timers from the local timer API. This will
allow us to remove ARM local timer support in the near future and
gets us closer to moving this driver to drivers/clocksource.

Acked-by: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>