clocksource/drivers: Set clockevent device cpumask to cpu_possible_mask

Currently, quite a few clockevent devices have cpumask set to
cpu_all_mask which should be fine. However, cpu_possible_mask is more
accurate and if there are any other clockevent devices in the system
which have cpumask set to cpu_possible_mask, then having cpu_all_mask
may result in issues (mostly boot hang with forever loops in
clockevents_notify_released).

So, lets replace all the clockevent device cpu_all_mask to
cpu_possible_mask in order to prevent above mentioned possible issue.

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Santosh Shilimkar <ssantosh@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

drivers/clocksource/timer-atcpit100.c

@@ -185,7 +185,7 @@ static struct timer_of to = {
 		.set_state_oneshot = atcpit100_clkevt_set_oneshot,
 		.tick_resume = atcpit100_clkevt_shutdown,
 		.set_next_event = atcpit100_clkevt_next_event,
-		.cpumask = cpu_all_mask,
+		.cpumask = cpu_possible_mask,
 	},
 
 	.of_irq = {