get_state_and_set_user packed get_state and set_user into one function,
which get pipeline/component state for a specific pipeline/component, if
success set the user to it.

v2:
- Rebase.
- Applied commit:
  b962a120 ("drm/atomic: integrate modeset lock with private objects")
  And delete our private modeset lock for pipeline.
Signed-off-by: James Qian Wang (Arm Technology China) <james.qian.wang@arm.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>