This patch adds i.MX8qxp LDB support.
Logics are added to make i.MX8qxp LDB cope with Mixel LVDS combo PHY.
Also, logics are added to handle pixel link quirks for i.MX8qxp LDB.

Signed-off-by: Liu Ying <victor.liu@nxp.com>
(cherry picked from commit 086248a0)