Convert some AVR GPIO operations to macros (#23424)

keyboards/ckeys/obelus/obelus.c

@@ -4,8 +4,8 @@ void matrix_init_kb(void) {
 	// put your keyboard start-up code here
 	// runs once when the firmware starts up
 	// Turn status LED on
-	DDRD |= (1<<6);
-	PORTD |= (1<<6);
+	gpio_set_pin_output(D6);
+	gpio_write_pin_high(D6);
 
 	matrix_init_user();
 }