Modify DFRobot Beetle pin_arduinos.h (#597)

Co-authored-by: Arya11111 <[email protected]>

Author: Arya11111

variants/dfrobot_beetle_rp2040/pins_arduino.h

@@ -37,7 +37,4 @@
 #define SPI_HOWMANY    (1u)
 #define WIRE_HOWMANY   (2u)
 
-#define __PIN_A0 (31u)
-#define __PIN_A1 (31u)
-
 #include "../generic/common.h"