GPU: ipu: fix lockup caused by pending chained interrupts

Even with the oops fixed by a previous patch, the system still fails to
kexec, due to a stuck chained interrupt locking the system.  We must
disable the child interrupts prior to setting up the irq chip to ensure
we don't get stuck here.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/ipu-v3/ipu-common.c

@@ -1107,6 +1107,9 @@ static int ipu_irq_init(struct ipu_soc *ipu)
 		return ret;
 	}
 
+	for (i = 0; i < IPU_NUM_IRQS; i += 32)
+		ipu_cm_write(ipu, 0, IPU_INT_CTRL(i / 32));
+
 	for (i = 0; i < IPU_NUM_IRQS; i += 32) {
 		gc = irq_get_domain_generic_chip(ipu->domain, i);
 		gc->reg_base = ipu->cm_reg;