drm/panel: introduce ebbg,ft8719 panel

Add DRM panel driver for EBBG FT8719 6.18" 2246x1080 DSI video mode
panel, which can be found on some Xiaomi Poco F1 phones. The panel's
backlight is managed through QCOM WLED driver.

Signed-off-by: Joel Selvaraj <jo@jsfamily.in>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/BY5PR02MB7009B6FA7F17A3DA36DDA44CD9DF9@BY5PR02MB7009.namprd02.prod.outlook.com