Add MAXI max11801 resistive touchscreen controller driver. This driver
uses Auto Mode and Aperture Mode.

Support for other max1180x devices can be added to this driver as well,
as they use almost the same register addresses and codes.

You can find data sheet here:
http://www.maxim-ic.com/datasheet/index.mvp/id/5943Signed-off-by: Zhang Jiejing <jiejing.zhang@freescale.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>