TFT_ShieldDetect() function
Check the availability of adafruit 1.8" TFT shield on top of STM32NUCLEO board. This is done by reading the state of IO PC.01 pin (mapped to JoyStick available on adafruit 1.8" TFT shield). If the state of PC.01 is high then the adafruit 1.8" TFT shield is available.
Return value
SHIELD_DETECTED: 1.8" TFT shield is available SHIELD_NOT_DETECTED: 1.8" TFT shield is not available