Input: add EETI eGalax I2C capacitive multi touch driver

This patch adds the EETI eGalax serial multi touch controller driver.

EETI eGalax serial touch screen controller is a I2C based multiple
capacitive touch screen controller, it can support 5 touch events maximum.

Signed-off-by: Zhang Jiejing <jiejing.zhang@freescale.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>