drm/msm: Move implicit sync handling to prepare_fb

In preparation for moving to atomic helpers, move the implicit sync
fence handling out of atomic commit and into the plane->prepare_fb()
hook. While we're at it, de-duplicate the mdp*_prepare_fb functions.

Changes in v4:
- Added

Reported-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

drivers/gpu/drm/msm/disp/mdp5/mdp5_plane.c

@@ -245,20 +245,6 @@ static const struct drm_plane_funcs mdp5_plane_funcs = {
 		.atomic_print_state = mdp5_plane_atomic_print_state,
 };
 
-static int mdp5_plane_prepare_fb(struct drm_plane *plane,
-				 struct drm_plane_state *new_state)
-{
-	struct mdp5_kms *mdp5_kms = get_kms(plane);
-	struct msm_kms *kms = &mdp5_kms->base.base;
-	struct drm_framebuffer *fb = new_state->fb;
-
-	if (!new_state->fb)
-		return 0;
-
-	DBG("%s: prepare: FB[%u]", plane->name, fb->base.id);
-	return msm_framebuffer_prepare(fb, kms->aspace);
-}
-
 static void mdp5_plane_cleanup_fb(struct drm_plane *plane,
 				  struct drm_plane_state *old_state)
 {
@@ -543,7 +529,7 @@ static void mdp5_plane_atomic_async_update(struct drm_plane *plane,
 }
 
 static const struct drm_plane_helper_funcs mdp5_plane_helper_funcs = {
-		.prepare_fb = mdp5_plane_prepare_fb,
+		.prepare_fb = msm_atomic_prepare_fb,
 		.cleanup_fb = mdp5_plane_cleanup_fb,
 		.atomic_check = mdp5_plane_atomic_check,
 		.atomic_update = mdp5_plane_atomic_update,