Update blink.c
Update blink.c

Add GT platform check

Signed-off-by: Marc Ernst <06fbbdd201d6f3a6bcfb944ac1af211b50670204@intel.com>
Signed-off-by: Thomas Ingleby <bb80a585db4bdbe09547a7483d1a31841fd0e0e8@intel.com>

intel-iot-devkit/iot-devkit-samples,intel-iot-devkit/iot-devkit-samples,intel-iot-devkit/iot-devkit-samples,intel-iot-devkit/iot-devkit-samples