clocksource/drivers/exynos_mct: Mark MCT device as CLOCK_EVT_FEAT_PERCPU

The "mct_tick" is a per-cpu clockevents device. Set the
CLOCK_EVT_FEAT_PERCPU feature to prevent e.g. mct_tick0 being unsafely
designated as the global broadcast timer and instead treat the device as
a per-cpu wakeup timer.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210608154341.10794-3-will@kernel.org