media: uapi: HEVC: Rename HEVC stateless controls with STATELESS prefix

Change HEVC  stateless controls names to V4L2_CID_STATELESS_HEVC instead
of V4L2_CID_MPEG_VIDEO_HEVC be coherent with v4l2 naming convention.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Tested-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>