Input: gpio_keys - disable hardware on suspend

Disable hardware if active when suspending if the hw can not
wake the system from suspend.

[Dmitry Torokhov: use input_dev->users instead of a separate flag]

Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Philippe Langlais <philippe.langlais@linaro.org>
Reviewed-by: Bengt Jonsson <bengt.g.jonsson@stericsson.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>