gpio.c: Add fix for dereferencing of a null pointer
gpio.c: Add fix for dereferencing of a null pointer

Signed-off-by: Cosmin Popescu <ad0650a18b5a7f98ec32b2ef02652ae4936b6d69@gmail.com>
Signed-off-by: Mihai Tudor Panu <a27de6130c5d32f5817bf40bb8b348582f37a8af@intel.com>

intel-iot-devkit/mraa,intel-iot-devkit/mraa,intel-iot-devkit/mraa,KurtE/mraa,KurtE/mraa,intel-iot-devkit/mraa,Propanu/mraa,Propanu/mraa,Propanu/mraa,Propanu/mraa,Propanu/mraa,intel-iot-devkit/mraa,g-vidal/mraa,KurtE/mraa,g-vidal/mraa,g-vidal/mraa,g-vidal/mraa,g-vidal/mraa,KurtE/mraa,KurtE/mraa