This patch adds basic support for Freescale MPR121 capacitive touch
sensor.  It's an i2c controller with up to 12 capacitance sensing inputs.

Product information (data sheet, application notes) can be found here:
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MPR121Signed-off-by: Zhang Jiejing <jiejing.zhang@freescale.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>