Updated missed reference.

Author: PontusO

src/boards/boards.c

@@ -96,7 +96,7 @@ void board_init(void)
   NRF_POWER->DCDCEN = 1;
 #endif
   // Make sure any custom inits are performed
-  extern_board_init();
+  board_init_extra();
 
 // When board is supplied on VDDH (and not VDD), this specifies what voltage the GPIO should run at
 // and what voltage is output at VDD. The default (0xffffffff) is 1.8V; typically you'll want