Input: gpio_keys - fix warning regarding uninitialized  'irq' variable

Commit f2d347ff70be453e ("Input: gpio_keys - add device tree support for
interrupt only keys") caused the following build warning:

drivers/input/keyboard/gpio_keys.c: In function 'gpio_keys_probe':
drivers/input/keyboard/gpio_keys.c:647:15: warning: 'irq' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/input/keyboard/gpio_keys.c:622:7: note: 'irq' was declared here

Move button->irq initialization into proper branch and get rid of the
temporary.

Reported-by: Olof's autobuilder <build@lixom.net>
Reported-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Input: add support for Elan eKTH I2C touchscreens

This driver supports Elan eKTH I2C touchscreen controllers. Note that these
are using custom protocol, as opposed to other Elan parts that use
HID-over-I2C and are supported by the standard HID-multitouch driver.

Signed-off-by: Scott Liu <scott.liu@emc.com.tw>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>