The struct rcar_du_encoder_data encoder::field describes the encoder
type, and the rcar_du_encoder_lvds_data and rcar_du_encoder_vga_data
structures describe connector properties. Rename them accordingly.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

The R-Car Display Unit (DU) DRM driver supports both superposition
processors and all eight planes in RGB and YUV formats with alpha
blending.

Only VGA and LVDS encoders and connectors are currently supported.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>