Update pins_arduino.h (#4211)

fix some mistake

Author: Gitshaoxiang

Diff for: variants/m5stack_atom/pins_arduino.h

@@ -20,7 +20,7 @@ static const uint8_t SCL = 32;
 
 static const uint8_t G12 = 12;
 static const uint8_t G19 = 19;
-static const uint8_t G22 = 21;
+static const uint8_t G21 = 21;
 static const uint8_t G22 = 22;
 static const uint8_t G23 = 23;
 static const uint8_t G25 = 25;
@@ -42,4 +42,9 @@ static const uint8_t DAC2 = 26;
 static const uint8_t ADC1 = 35;
 static const uint8_t ADC2 = 36;
 
+static const uint8_t SS    = 19;
+static const uint8_t MOSI  = 33;
+static const uint8_t MISO  = 23;
+static const uint8_t SCK   = 22;
+
 #endif /* Pins_Arduino_h */