drm/tinydrm: add driver for ILI9225 panels

This adds a new driver for display panels based on the Ilitek ILI9225
controller.

This was developed for a no-name panel with a red PCB that is commonly
marketed for Arduino. See <https://github.com/Nkawu/TFT_22_ILI9225

>.

Signed-off-by: David Lechner <david@lechnology.com>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1511122328-31133-5-git-send-email-david@lechnology.com