codal_app/microbithal: Fix define of MICROBIT_HAL_PIN_P11 to be 11.

Fixes issue #136.

Signed-off-by: Damien George <damien@micropython.org>

Author: dpgeorge

src/codal_app/microbithal.h

@@ -51,7 +51,7 @@ extern "C" {
 #define MICROBIT_HAL_PIN_P8     (8)
 #define MICROBIT_HAL_PIN_P9     (9)
 #define MICROBIT_HAL_PIN_P10    (10)
-#define MICROBIT_HAL_PIN_P11    (12)
+#define MICROBIT_HAL_PIN_P11    (11)
 #define MICROBIT_HAL_PIN_P12    (12)
 #define MICROBIT_HAL_PIN_P13    (13)
 #define MICROBIT_HAL_PIN_P14    (14)