media: staging: media: rkvdec: Update TODO list

VP9 support has been added to the driver by commit f25709c4
("media: rkvdec: Add the VP9 backend").
And the VP9 uABI was merged with commit b88dbe38
("media: uapi: Add VP9 stateless decoder controls").

The remaining codec that keeps this driver in staging is HEVC.
Update the TODO list accordingly.
Signed-off-by: NSebastian Fricke <sebastian.fricke@collabora.com>
Reviewed-by: NNicolas Dufresne <nicolas.dufresne@collabora.com>
Signed-off-by: NHans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: NMauro Carvalho Chehab <mchehab@kernel.org>

drivers/staging/media/rkvdec/TODO

-* Support for VP9 is planned for this driver.
+* Support for HEVC is planned for this driver.
 
-  Given the V4L controls for those CODECs will be part of
+  Given the V4L controls for that CODEC will be part of
   the uABI, it will be required to have the driver in staging.
 
   For this reason, we are keeping this driver in staging for now.