media: staging: media: imx: imx7-media-csi: Drop duplicate link creation

The imx_media_create_csi2_links() creates a media controller link
between the CSI-2 receiver and the next entity in the pipeline, which
can be either a video mux (handled by the video-mux driver) or the CSI
bridge itself. This isn't needed, as the link is already created either
by the video-mux driver or by the imx7-media-csi driver itself (in
imx7_csi_notify_bound()).

Drop imx_media_create_csi2_links(), which allows dropping the CSI bridge
subdev grp_id.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>