input: synaptics_i2c_rmi4: Allow GPIOs to suspend during sleep

In order to save power, enable GPIOs to go into suspened mode
during sleep by freeing them, and re-requesting on wake.

Change-Id: I5b1839f5a15fff0bad13b636be35079a8687fa6a
Signed-off-by: Amy Maloche <amaloche@codeaurora.org>