drm/i915: Fix for_each_intel_plane_mask definition

Using for_each_intel_plane_mask() fails because of an extra bracket,
remove the bracket so we can use it in the next commit.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004113514.17064-3-maarten.lankhorst@linux.intel.comReviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>

drivers/gpu/drm/i915/display/intel_display.h

@@ -350,7 +350,7 @@ enum phy_fia {
 			    &(dev)->mode_config.plane_list,		\
 			    base.head)					\
 		for_each_if((plane_mask) &				\
-			    drm_plane_mask(&intel_plane->base)))
+			    drm_plane_mask(&intel_plane->base))
 
 #define for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane)	\
 	list_for_each_entry(intel_plane,				\