drm: lcdif: Add multiple encoders and first bridges support

The single LCDIF embedded in i.MX93 SoC may drive multiple displays
simultaneously.  Look at LCDIF output port's remote port parents to
find all enabled first bridges.  Add an encoder for each found bridge
and attach the bridge to the encoder.  This is a preparation for
adding i.MX93 LCDIF support.

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230510092450.4024730-6-victor.liu@nxp.com