drm: Rely on mode_config data for fb_helper initialization

Instead of receiving the num_crts as a parameter, we can read it
directly from the mode_config structure.  I audited the drivers that
invoke this helper and I believe all of them initialize the mode_config
struct accordingly, prior to calling the fb_helper.

I used the following coccinelle hack to make this transformation, except
for the function headers and comment updates.  The first and second
rules are split because I couldn't find a way to remove the unused
temporary variables at the same time I removed the parameter.

// <smpl>
@r@
expression A,B,D,E;
identifier C;
@@
(
- drm_fb_helper_init(A,B,C,D)
+ drm_fb_helper_init(A,B,D)
|
- drm_fbdev_cma_init_with_funcs(A,B,C,D,E)
+ drm_fbdev_cma_init_with_funcs(A,B,D,E)
|
- drm_fbdev_cma_init(A,B,C,D)
+ drm_fbdev_cma_init(A,B,D)
)

@@
expression A,B,C,D,E;
@@
(
- drm_fb_helper_init(A,B,C,D)
+ drm_fb_helper_init(A,B,D)
|
- drm_fbdev_cma_init_with_funcs(A,B,C,D,E)
+ drm_fbdev_cma_init_with_funcs(A,B,D,E)
|
- drm_fbdev_cma_init(A,B,C,D)
+ drm_fbdev_cma_init(A,B,D)
)

@@
identifier r.C;
type T;
expression V;
@@
- T C;
<...
when != C
- C = V;
...>
// </smpl>

Changes since v1:
 - Rebased on top of the tip of drm-misc-next.
 - Remove mention to sti since a proper fix got merged.

Suggested-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.co.uk>
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170202162640.27261-1-krisman@collabora.co.uk

drivers/gpu/drm/hisilicon/kirin/kirin_drm_drv.c

@@ -59,8 +59,7 @@ static void kirin_fbdev_output_poll_changed(struct drm_device *dev)
 		drm_fbdev_cma_hotplug_event(priv->fbdev);
 	} else {
 		priv->fbdev = drm_fbdev_cma_init(dev, 32,
-				dev->mode_config.num_crtc,
-				dev->mode_config.num_connector);
+						 dev->mode_config.num_connector);
 		if (IS_ERR(priv->fbdev))
 			priv->fbdev = NULL;
 	}