drm: Docbook fixes

Bunch of small leftovers spotted by looking at the make htmldocs output.

I've left out dp mst, there's too much amiss there.

v2: Also add the missing parameter docbook in the dp mst code - Dave
Airlie correctly pointed out that we don't actually want kerneldoc for
the missing structure members in header files.

Cc: Dave Airlie <airlied@gmail.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 285e62a..f09b7521 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3512,9 +3512,10 @@
  * @flags: flags specifying the property type
  * @name: name of the property
  * @props: enumeration lists with property bitflags
- * @num_values: number of pre-defined values
+ * @num_props: size of the @props array
+ * @supported_bits: bitmask of all supported enumeration values
  *
- * This creates a new generic drm property which can then be attached to a drm
+ * This creates a new bitmask drm property which can then be attached to a drm
  * object with drm_object_attach_property. The returned property object must be
  * freed with drm_property_destroy.
  *