greybus: i2c-gb: add irq protocol and irqchip support

This is the crude hack of Greybus gpio irq support masquerading
as an I2C irq. By hiding the irq in the I2C protocol driver, we
avoid the current kernel limitation on handling of GPIO hot unplug.

This hack registers an irqchip with the Greybus i2c adapter that
has one source. This is intended to be used only with the December
demo. The protocol is, however, the same that is being used in
for actual GPIO interrupt support which leverages the standard
gpiolib irqchip helpers.

NOTE: DO NOT MERGE THIS TO GREYBUS MASTER!!!

Signed-off-by: Matt Porter <mporter@linaro.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
greybus: i2c-gb: add support to instantiate an mms114 touchscreen device

This is yet another cute embedded nonsense hack which instantiates an mms114
i2c touchscreen device along with the board info and platform data necessary
for the driver. It is intended only to support the December demo.

NOTE: DO NOT MERGE THIS TO GREYBUS MASTER!!!

Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Matt Porter <mporter@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>