drm/panel: simple: Add EDT panel support

EDT ET043080DH6-GP is a 4.3" WQVGA 480x272 RGB LCD panel used on the iWave
Generic SODIMM Development Platform.

Changes in v2:
	-added mandatory .connector_type field
	-changed the .bus_format MEDIA_BUS_FMT_RGB666_1X18

Signed-off-by: Marian-Cristian Rotariu <marian-cristian.rotariu.rb@bp.renesas.com>
Reviewed-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1580386118-22895-3-git-send-email-marian-cristian.rotariu.rb@bp.renesas.com