Remove unnecessary BUG_ON in irq.c

From: Alexander Nyberg

Signed-off-by: Andi Kleen <ak@suse.de>

Index: linux/arch/x86_64/kernel/irq.c
===================================================================
--- linux.orig/arch/x86_64/kernel/irq.c
+++ linux/arch/x86_64/kernel/irq.c
@@ -99,7 +99,6 @@ asmlinkage unsigned int do_IRQ(struct pt
 	unsigned irq = regs->orig_rax & 0xff;
 
 	irq_enter();
-	BUG_ON(irq > 256);
 
 	__do_IRQ(irq, regs);
 	irq_exit();