[ARM] 4661/1: fix do_undefinstr wrt the enabling of IRQs

The lock is acquired with spin_lock_irqsave() and released in the
not-found case with spin_unlock_irqrestore().
Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/kernel/traps.c

@@ -327,7 +327,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 		if ((instr & hook->instr_mask) == hook->instr_val &&
 		    (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val) {
 			if (hook->fn(regs, instr) == 0) {
-				spin_unlock_irq(&undef_lock);
+				spin_unlock_irqrestore(&undef_lock, flags);
 				return;
 			}
 		}