drm/msm: dpu: Don't use power_event for vbif_init_memtypes

power_events are only used for pm_runtime, and that's all handled in
dpu_kms. So just call vbif_init_memtypes at the correct times.

Changes in v2:
- Removed obsolete comment (Jeykumar)

Cc: Jeykumar Sankaran <jsanka@codeaurora.org>
Reviewed-by: Jeykumar Sankaran <jsanka@codeaurora.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>

Signed-off-by: Rob Clark <robdclark@gmail.com>