drm/mediatek: dp: Replace usage of drm_bridge_chain_ functions

Commit f70ac097

 ("drm/mediatek: Add MT8195 Embedded DisplayPort
driver") added usage of the drm_bridge_chain_ functions which are
to be deprecated.

Replace with the drm_atomic_bridge_chain_ variants using the
current state.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20221205173328.1395350-3-dave.stevenson@raspberrypi.com
Signed-off-by: Maxime Ripard <maxime@cerno.tech>