drm/tidss: Mark AM65x OLDI code separately

drm/tidss: Mark AM65x OLDI code separately

The dss dt schema and the tidss driver have kept the single-link OLDI in
AM65x integrated with the parent video-port (VP) from DSS (as the OLDI
configuration happens from the source VP only).
To help configure the dual-lvds modes that the OLDI has to offer in
devices AM62x and later, a new OLDI bridge driver will be introduced.

Mark the existing OLDI code separately by renaming all the current OLDI
identifiers with the 'AM65X_' prefix in tidss driver, to help
distinguish from the upcoming OLDI bridge driver.

Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: Aradhya Bhatia <aradhya.bhatia@linux.dev>
Link: https://lore.kernel.org/r/20250528122544.817829-4-aradhya.bhatia@linux.dev
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>