drm: Add plane->name and use it in debug prints

Show a sensible name for the plane in debug mesages. The driver
may supply its own name, otherwise the core genrates the name
("plane-0", "plane-1" etc.).

v2: kstrdup() the name passed by the caller (Jani)
v3: Generate a default name if the driver doesn't supply one

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1449592922-5545-7-git-send-email-ville.syrjala@linux.intel.com
diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 6ba3fe5..63f925b 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -545,8 +545,8 @@
 
 		ret = funcs->atomic_check(plane, plane_state);
 		if (ret) {
-			DRM_DEBUG_ATOMIC("[PLANE:%d] atomic driver check failed\n",
-					 plane->base.id);
+			DRM_DEBUG_ATOMIC("[PLANE:%d:%s] atomic driver check failed\n",
+					 plane->base.id, plane->name);
 			return ret;
 		}
 	}