drm: lcdif: Check consistent bus format and flags across first bridges

The single LCDIF embedded in i.MX93 SoC may drive multiple displays
simultaneously.  Check bus format and flags across first bridges in
->atomic_check() to ensure they are consistent.  This is a preparation
for adding i.MX93 LCDIF support.

Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230510092450.4024730-5-victor.liu@nxp.com