[MIPS] i8259: Add disable method.

After 76d2160147, the qemu NE2000 was
frequently producing WATCHDOG timeouts.

Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/i8259.c

@@ -36,6 +36,7 @@ void mask_and_ack_8259A(unsigned int);
 static struct irq_chip i8259A_chip = {
 	.name		= "XT-PIC",
 	.mask		= disable_8259A_irq,
+	.disable	= disable_8259A_irq,
 	.unmask		= enable_8259A_irq,
 	.mask_ack	= mask_and_ack_8259A,
 };