drm/msm: Add hrtimer + kthread_work helper

Before open-coding this a 2nd time, add a helper.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Link: https://lore.kernel.org/r/20210927230455.1066297-1-robdclark@gmail.com


Signed-off-by: Rob Clark <robdclark@chromium.org>