There is no gpio functions used in the driver that is exported
by the gpio.h header, so remove this unneeded header.

Signed-off-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20191026185958.24158-2-festevam@gmail.com


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>