drm/i915: Pass crtc to intel_update_watermarks()

Passing the appropriate crtc to intel_update_watermarks() should help
in avoiding needless work in the future.

v2: Avoid clash with internal 'crtc' variable in some wm functions

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 1fb01b5..81ba5bb 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -361,7 +361,7 @@
 			  int target, int refclk,
 			  struct dpll *match_clock,
 			  struct dpll *best_clock);
-	void (*update_wm)(struct drm_device *dev);
+	void (*update_wm)(struct drm_crtc *crtc);
 	void (*update_sprite_wm)(struct drm_plane *plane,
 				 struct drm_crtc *crtc,
 				 uint32_t sprite_width, int pixel_size,