drm/fourcc: Pass the format_info pointer to drm_format_plane_cpp

So far, the drm_format_plane_cpp function was operating on the format's
fourcc and was doing a lookup to retrieve the drm_format_info structure and
return the cpp.

However, this is inefficient since in most cases, we will have the
drm_format_info pointer already available so we shouldn't have to perform a
new lookup. Some drm_fourcc functions also already operate on the
drm_format_info pointer for that reason, so the API is quite inconsistent
there.

Let's follow the latter pattern and remove the extra lookup while being a
bit more consistent. In order to be extra consistent, also rename that
function to drm_format_info_plane_cpp and to a static function in the
header to match the current policy.

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/32aa13e53dbc98a90207fd290aa8e79f785fb11e.1558002671.git-series.maxime.ripard@bootlin.com
diff --git a/drivers/gpu/drm/radeon/radeon_fb.c b/drivers/gpu/drm/radeon/radeon_fb.c
index 1298b84..dbf596f 100644
--- a/drivers/gpu/drm/radeon/radeon_fb.c
+++ b/drivers/gpu/drm/radeon/radeon_fb.c
@@ -125,6 +125,7 @@ static int radeonfb_create_pinned_object(struct radeon_fbdev *rfbdev,
 					 struct drm_mode_fb_cmd2 *mode_cmd,
 					 struct drm_gem_object **gobj_p)
 {
+	const struct drm_format_info *info;
 	struct radeon_device *rdev = rfbdev->rdev;
 	struct drm_gem_object *gobj = NULL;
 	struct radeon_bo *rbo = NULL;
@@ -135,7 +136,8 @@ static int radeonfb_create_pinned_object(struct radeon_fbdev *rfbdev,
 	int height = mode_cmd->height;
 	u32 cpp;
 
-	cpp = drm_format_plane_cpp(mode_cmd->pixel_format, 0);
+	info = drm_get_format_info(rdev->ddev, mode_cmd);
+	cpp = drm_format_info_plane_cpp(info, 0);
 
 	/* need to align pitch with crtc limits */
 	mode_cmd->pitches[0] = radeon_align_pitch(rdev, mode_cmd->width, cpp,