Setting GPIOs during probe causes null pointer deference when
GPIOLIB was not selected by Kconfig. Initialize driver private
field before calling set gpios.

It is regressing bug since 4.9.

Fixes: 07fdf7d9 ("[media] cxd2820r: add I2C driver bindings")
Reported-by: Chris Rankin <rankincj@gmail.com>
Tested-by: Chris Rankin <rankincj@gmail.com>
Tested-by: Håkan Lennestål <hakan.lennestal@gmail.com>
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Antti Palosaari <crope@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>