[MIPS] PB1200: Remove duplicate definitions

Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/au1000/pb1200/board_setup.c

@@ -151,11 +151,7 @@ void __init board_setup(void)
 #endif
 
 	/* Setup Pb1200 External Interrupt Controller */
-	{
-		extern void (*board_init_irq)(void);
-		extern void _board_init_irq(void);
 	board_init_irq = _board_init_irq;
-	}
 }
 
 int