drm/bridge: microchip-lvds: Remove unused drm_panel and redundant port node lookup

drm/bridge: microchip-lvds: Remove unused drm_panel and redundant port node lookup

Drop the unused drm_panel field from the mchp_lvds structure, and remove
the unnecessary port device node lookup, as devm_drm_of_get_bridge()
already performs the required checks internally.

Signed-off-by: Dharma Balasubiramani <dharma.b@microchip.com>
Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patch.msgid.link/20250625-microchip-lvds-v6-1-7ce91f89d35a@microchip.com
Signed-off-by: Manikandan Muralidharan <manikandan.m@microchip.com>