clocksource/drivers/timer-ti-dm: Use runtime PM directly and check errors

clocksource/drivers/timer-ti-dm: Use runtime PM directly and check errors

Use pm_runtime_resume_and_get() and check for a possible error returned.

We want to do this as omap_dm_timer_enable() and omap_dm_timer_disable()
are exposed to the pwm and remoteproc drivers, and in the following patch
we turn struct omap_dm_timer into a cookie used by the exposed functions
only.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Reviewed-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Link: https://lore.kernel.org/r/20220815131250.34603-7-tony@atomide.com
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>