Fix some pins definition

Author: Tinyu-Zhao

Diff for: variants/m5stack_atoms3/pins_arduino.h

@@ -34,7 +34,7 @@ static const uint8_t RXD2 = 2;
 static const uint8_t SDA = 38;
 static const uint8_t SCL = 39;
 
-static const uint8_t SS   = 15;
+static const uint8_t CS   = 15;
 static const uint8_t MOSI = 21;
 static const uint8_t MISO = -1;
 static const uint8_t SCK  = 17;