MIPS: OCTEON: irq: Fix potential NULL pointer dereference

There is a potential NULL pointer dereference in case kzalloc()
fails and returns NULL.

Fix this by adding a NULL check on *cd*

This bug was detected with the help of Coccinelle.

Fixes: 64b139f ("MIPS: OCTEON: irq: add CIB and other fixes")
Cc: stable@vger.kernel.org
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/cavium-octeon/octeon-irq.c

@@ -2199,6 +2199,9 @@ static int octeon_irq_cib_map(struct irq_domain *d,
 	}
 
 	cd = kzalloc(sizeof(*cd), GFP_KERNEL);
+	if (!cd)
+		return -ENOMEM;
+
 	cd->host_data = host_data;
 	cd->bit = hw;