Update GPIO pin naming.

coleco.c

@@ -24,7 +24,7 @@ const GpioPin* const pin_right = &gpio_ext_pb2;
 const GpioPin* const pin_left = &gpio_ext_pc3;
 const GpioPin* const pin_code0 = &gpio_ext_pa7;
 const GpioPin* const pin_code1 = &gpio_ext_pa4;
-const GpioPin* const pin_code2 = &ibutton_gpio;
+const GpioPin* const pin_code2 = &gpio_ibutton;
 const GpioPin* const pin_code3 = &gpio_ext_pc1;
 const GpioPin* const pin_fire = &gpio_ext_pb3;
 const GpioPin* const pin_alt = &gpio_usart_tx;