ARM: OMAP2+: timer: Add suspend-resume callbacks for clkevent device

OMAP timer code registers two timers - one as clocksource
and one as clockevent. Since AM33XX has only one usable timer
in the WKUP domain one of the timers needs suspend-resume
support to restore the configuration to pre-suspend state.

commit adc78e6b ("timekeeping: Add suspend and resume
of clock event devices") introduced .suspend and .resume
callbacks for clock event devices. Leverage these
callbacks to have AM33XX clockevent timer behave properly
across system suspend. Extend the use of the .suspend and
.resume callbacks used by am335x clockevent to am437x as well.

Signed-off-by: Dave Gerlach <d-gerlach@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>