drm/bridge: tc358767: Switch to devm MIPI-DSI helpers

DSI device registering and attaching needs to be undone upon
deregistration. This fixes module unload/load.

Fixes: bbfd3190 ("drm/bridge: tc358767: Add DSI-to-DPI mode support")
Signed-off-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230517122107.1766673-1-alexander.stein@ew.tq-group.com