clocksource: exynos_mct: Clear timer interrupt when shutdown

clocksource: exynos_mct: Clear timer interrupt when shutdown

When shutting down the timer, ensure that after we have stopped the
timer any pending interrupts are cleared. This fixes a problem when
suspending, as interrupts are disabled before the timer is stopped,
so the timer interrupt may still be asserted, preventing the system
entering a low power state when the wfi is executed.

Signed-off-by: Stuart Menefy <stuart.menefy@mathembedded.com>
[pending patch for mainline]
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Change-Id: I2068bbadeb5e778bb81f772693e30a47e64dd77c