MLK-16036 drm/imx: ldb: Avoid early return when getting aux PHY in dual mode

In dual mode, we return too early from ->bind when we get
the auxiliary channel's PHY.  This causes we miss the logics
to set driver data, get ldb alias id and initialize pixel
link(if necessary).  This patch fixes the issue here by
tweaking the driver logic to do component binding properly.

Signed-off-by: Liu Ying <victor.liu@nxp.com>