Migrate broadcast-hrtimer driver to the new 'set-state' interface
provided by clockevents core, the earlier 'set-mode' interface is marked
obsolete now.

Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NDaniel Lezcano <daniel.lezcano@linaro.org>