mfd: Add driver for Atmel Microcontroller on iPaq h3xxx

This adds a driver for the Atmel Microcontroller found on the
iPAQ h3xxx series. This device handles some keys, the
touchscreen, and the battery monitoring.

This is a port of a driver from handhelds.org 2.6.21 kernel,
written by Alessandro Gardich based on Andrew Christians
original HAL-driver. It has been heavily cleaned and
converted to mfd-core by Dmitry Artamonow and rewritten
again for the v3.x series kernels by Linus Walleij,
bringing back some of the functionality lost from Andrew's
original driver.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Alessandro Gardich <gremlin@gremlin.it>
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>