This adds a new driver for display panels that use the Ilitek ILI9341
controller. It currently supports a single display panel, namely
the YX240QV29-T (e.g. Adafruit 2.4" TFT).

The init sequence is from the Adafruit Python library for the ILI9341
controller. https://github.com/adafruit/Adafruit_Python_ILI9341Signed-off-by: NDavid Lechner <david@lechnology.com>
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: NNoralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180525193623.15533-5-david@lechnology.com