pic16bit/pic16bit_mphal: Use MP_REGISTER_ROOT_POINTER().

This uses MP_REGISTER_ROOT_POINTER() to register keyboard_interrupt_obj
and removes the same from mpconfigport.h.

Signed-off-by: David Lechner <david@pybricks.com>

ports/pic16bit/mpconfigport.h

@@ -91,9 +91,6 @@ typedef int mp_off_t;
 
 #define MP_STATE_PORT MP_STATE_VM
 
-#define MICROPY_PORT_ROOT_POINTERS \
-    mp_obj_t keyboard_interrupt_obj; \
-
 #define MICROPY_MPHALPORT_H "pic16bit_mphal.h"
 #define MICROPY_HW_BOARD_NAME "dsPICSK"
 #define MICROPY_HW_MCU_NAME "dsPIC33"

ports/pic16bit/pic16bit_mphal.c

@@ -86,3 +86,5 @@ void mp_hal_stdout_tx_strn_cooked(const char *str, size_t len) {
         uart_tx_char(*str++);
     }
 }
+
+MP_REGISTER_ROOT_POINTER(mp_obj_t keyboard_interrupt_obj);