drm: bridge: it66121: Simplify probe()

Simplify probe() by replacing of_device_get_match_data() and ID lookup
for retrieving match data by i2c_get_match_data().

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230818191817.340360-3-biju.das.jz@bp.renesas.com