UPSTREAM: clocksource/drivers/rockchip: Add the dynamic irq flag to the timer

UPSTREAM: clocksource/drivers/rockchip: Add the dynamic irq flag to the timer

The rockchip timer is a broadcast timer. Add the CLOCK_EVT_FEAT_DYNIRQ flag
and set the cpumask to all possible cpus to save power by avoiding
unnecessary wakeups and IPIs.

BUG=chrome-os-partner:54522
TEST=Tested on gru, cat /proc/interrupts |grep timer

Change-Id: Ic7de570f35921a292e4687c2bcf408b37334f781
Signed-off-by: Huang Tao <huangtao@rock-chips.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Heiko Stuebner <heiko@sntech.de>
Tested-by: Jianqun Xu <jay.xu@rock-chips.com>
Signed-off-by: Caesar Wang <wxt@rock-chips.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
(cherry picked from git.linaro.org/people/daniel.lezcano/linux.git clockevents/next
 commit 11932c2ac6f8c0f20f12a38569a36f0d1b5cfd6b)
Reviewed-on: https://chromium-review.googlesource.com/353976
Reviewed-by: Douglas Anderson <dianders@chromium.org>