drm/panel: simple: Add support for EDT ETM0350G0DH6 panel

This patch adds support for the EDT ETM0350G0DH6 3.5" (320x240) lcd
panel to DRM simple panel driver.

Signed-off-by: Stefan Riedmueller <s.riedmueller@phytec.de>
Signed-off-by: Yunus Bas <y.bas@phytec.de>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210709200349.2665205-2-y.bas@phytec.de