drm/tidss: Add OLDI bridge support

The AM62x and AM62Px SoCs feature 2 OLDI TXes each, which makes it
possible to connect them in dual-link or cloned single-link OLDI display
modes. The current OLDI support in tidss_dispc.c can only support for
a single OLDI TX, connected to a VP and doesn't really support
configuration of OLDIs in the other modes. The current OLDI support in
tidss_dispc.c also works on the principle that the OLDI output can only
be served by one, and only one, DSS video-port. This isn't the case in
the AM62Px SoC, where there are 2 DSS controllers present that share the
OLDI TXes.

Having their own devicetree and their own bridge entity will help
support the various display modes and sharing possiblilities of the OLDI
hardware.

For all these reasons, add support for the OLDI TXes as DRM bridges.

Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
Tested-by: Michael Walle <mwalle@kernel.org> # on am67a
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://lore.kernel.org/r/20250528122544.817829-5-aradhya.bhatia@linux.dev


Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>