drm/panel: Add Novatek NT39016 panel support

Add support for display panels built around the Novatek NT39016 display
controller, as found on e.g. the King Display KD035G6-54NT 24-bit
320x240 3.5" LCD panel which equips the GCW Zero open-source handheld
gaming console.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Maarten ter Huurne <maarten@treewalker.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190603152555.23527-2-paul@crapouillou.net