Input: goodix - support Goodix gt5688

From what I've seen in vendor trees it's fine to treat this as gt1x¹.
Tested on the Purism Librem 5 Devkit (Rocktech JH057N00900 panel).

[1]: https://github.com/TadiT7/android_kernel_mtk-4.4/tree/master/drivers/input/touchscreen/mediatek/GT5688



Signed-off-by: Guido Günther <agx@sigxcpu.org>
Reviewed-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>