drm: Nuke fb->depth

Replace uses of fb->depth with fb->format->depth. Less duplicate
information is a good thing.

@@
struct drm_framebuffer *fb;
expression E;
@@
 drm_helper_mode_fill_fb_struct(...) {
	...
-	fb->depth = E;
	...
 }

@@
struct nouveau_framebuffer *fb;
@@
- fb->base.depth
+ fb->base.format->depth

@@
struct drm_framebuffer fb;
@@
- fb.depth
+ fb.format->depth

@@
struct drm_framebuffer *fb;
@@
- fb->depth
+ fb->format->depth

@@
struct drm_framebuffer fb;
@@
- (fb.format->depth)
+ fb.format->depth

@@
struct drm_framebuffer *fb;
@@
- (fb->format->depth)
+ fb->format->depth

@@
@@
 struct drm_framebuffer {
	 ...
-	 unsigned int depth;
	 ...
 };

v2: Drop the vmw stuff (Daniel)
    Rerun spatch due to code changes

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1481751095-18249-1-git-send-email-ville.syrjala@linux.intel.com

drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c

@@ -598,7 +598,7 @@ static int do_dmabuf_define_gmrfb(struct vmw_private *dev_priv,
 	struct vmw_dma_buffer *buf =
 		container_of(framebuffer, struct vmw_framebuffer_dmabuf,
 			     base)->buffer;
-	int depth = framebuffer->base.depth;
+	int depth = framebuffer->base.format->depth;
 	struct {
 		uint32_t header;
 		SVGAFifoCmdDefineGMRFB body;