usb: typec: nb7vpq904m: switch to DRM_AUX_BRIDGE

Switch to using the new DRM_AUX_BRIDGE helper to create the
transparent DRM bridge device instead of handcoding corresponding
functionality.

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>