drm/i915: Clarify sprite plane function names (v4)

A few of the sprite-related function names in i915 are very similar
(e.g., intel_enable_planes() vs intel_crtc_enable_planes()) and don't
make it clear whether they only operate on sprite planes, or whether
they also apply to all universal plane types.  Rename a few functions to
be more consistent with our function naming for primary/cursor planes or
to clarify that they apply specifically to sprite planes:

 - s/intel_disable_planes/intel_disable_sprite_planes/
 - s/intel_enable_planes/intel_enable_sprite_planes/

Also, drop the sprite-specific intel_destroy_plane() and just use
the type-agnostic intel_plane_destroy() function.  The extra 'disable'
call that intel_destroy_plane() did is unnecessary since the plane will
already be disabled due to framebuffer destruction by the point it gets
called.

v2: Earlier consolidation patches have reduced the number of functions
    we need to rename here.

v3: Also rename intel_plane_funcs vtable to intel_sprite_plane_funcs
    for consistency with primary/cursor.  (Ander)

v4: Convert comment for intel_plane_destroy() to kerneldoc now that it
    is no longer a static function.  (Ander)

Reviewed-by(v1): Bob Paauwe <bob.j.paauwe@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index 1dfdccb..bb67ae7 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -1306,14 +1306,6 @@
 	}
 }
 
-static void intel_destroy_plane(struct drm_plane *plane)
-{
-	struct intel_plane *intel_plane = to_intel_plane(plane);
-	intel_disable_plane(plane);
-	drm_plane_cleanup(plane);
-	kfree(intel_plane);
-}
-
 int intel_sprite_set_colorkey(struct drm_device *dev, void *data,
 			      struct drm_file *file_priv)
 {
@@ -1413,10 +1405,10 @@
 				  intel_plane->src_w, intel_plane->src_h);
 }
 
-static const struct drm_plane_funcs intel_plane_funcs = {
+static const struct drm_plane_funcs intel_sprite_plane_funcs = {
 	.update_plane = intel_update_plane,
 	.disable_plane = intel_disable_plane,
-	.destroy = intel_destroy_plane,
+	.destroy = intel_plane_destroy,
 	.set_property = intel_plane_set_property,
 };
 
@@ -1553,7 +1545,7 @@
 	intel_plane->commit_plane = intel_commit_sprite_plane;
 	possible_crtcs = (1 << pipe);
 	ret = drm_universal_plane_init(dev, &intel_plane->base, possible_crtcs,
-				       &intel_plane_funcs,
+				       &intel_sprite_plane_funcs,
 				       plane_formats, num_plane_formats,
 				       DRM_PLANE_TYPE_OVERLAY);
 	if (ret) {