drm: Replace drm_format_num_planes() with fb->format->num_planes

Replace drm_format_num_planes(fb->pixel_format) with just
fb->format->num_planes. Avoids the expensive format info lookup.

@@
struct drm_framebuffer *a;
struct drm_framebuffer b;
@@
(
- drm_format_num_planes(a->pixel_format)
+ a->format->num_planes
|
- drm_format_num_planes(b.pixel_format)
+ b.format->num_planes
)

@@
struct drm_plane_state *a;
struct drm_plane_state b;
@@
(
- drm_format_num_planes(a->fb->pixel_format)
+ a->fb->format->num_planes
|
- drm_format_num_planes(b.fb->pixel_format)
+ b.fb->format->num_planes
)

@@
struct drm_framebuffer *a;
identifier T;
@@
  T = a->pixel_format
<+...
- drm_format_num_planes(T)
+ a->format->num_planes
...+>

@@
struct drm_framebuffer b;
identifier T;
@@
  T = b.pixel_format
<+...
- drm_format_num_planes(T)
+ b.format->num_planes
...+>

v2: Rerun spatch due to code changes

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1481751022-18015-1-git-send-email-ville.syrjala@linux.intel.com

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

@@ -699,7 +699,7 @@ static int mdp5_plane_mode_set(struct drm_plane *plane,
 	unsigned long flags;
 	int ret;
 
-	nplanes = drm_format_num_planes(fb->pixel_format);
+	nplanes = fb->format->num_planes;
 
 	/* bad formats should already be rejected: */
 	if (WARN_ON(nplanes > pipe2nclients(pipe)))