drm/arm: hdlcd: Set the CRTC's port before binding the encoder.

The component-based encoder(s) used by HDLCD expect the CRTC port
to be set before binding in order to find the right endpoint.
Without this patch, the TDA19988 encoder driver prints a warning
"Falling back to first CRTC".

Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com>