Update pins_arduino.h (#10610)

The correct pin is GPIO4.

Author: CelliesProjects

Diff for: variants/m5stack_fire/pins_arduino.h

@@ -9,7 +9,7 @@ static const uint8_t RX = 3;
 static const uint8_t SDA = 21;
 static const uint8_t SCL = 22;
 
-static const uint8_t SS = 5;
+static const uint8_t SS = 4;
 static const uint8_t MOSI = 23;
 static const uint8_t MISO = 19;
 static const uint8_t SCK = 18;