Add MIPI-DSI support to Verdin AM62.

Verdin AM62 has a MIPI DSI interface on the edge connector, this is
provided with a Toshiba TC358778 DPI to MIPI-DSI bridge connected to the
DSS DPI port with a 18-bit width parallel bus.
Signed-off-by: Francesco Dolcini <francesco.dolcini@toradex.com>
Link: https://lore.kernel.org/r/20230812191123.14779-1-francesco@dolcini.itSigned-off-by: Nishanth Menon <nm@ti.com>