drm: Fix plane SIZE_HINTS property docs

Fix the typos in the plane SIZE_HINTS kernel docs.

Reported-by: Stephen Rothwell <[e-mail]>
Fixes: 9677547d8362 ("drm: Introduce plane SIZE_HINTS property")
Signed-off-by: Ville Syrjälä <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Reviewed-by: Dmitry Baryshkov <[e-mail]>

drivers/gpu/drm/drm_plane.c

···
 EXPORT_SYMBOL(drm_plane_create_scaling_filter_property);
 
 /**
- * drm_plane_add_size_hint_property - create a size hint property
+ * drm_plane_add_size_hints_property - create a size hints property
  *
  * @plane: drm plane
  * @hints: size hints

include/drm/drm_mode_config.h

···
 	struct drm_property *modifiers_property;
 
 	/**
-	 * @size_hints_propertty: Plane SIZE_HINTS property.
+	 * @size_hints_property: Plane SIZE_HINTS property.
 	 */
 	struct drm_property *size_hints_property;