[SPARC]: Fix EBUS use of uninitialized variable.

If of_get_property() fails, it returns NULL and the 'len'
parameter is undefined.  So we need to explicitly set len
to zero in such cases.

Noticed by Al Viro.
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/kernel/ebus.c

@@ -156,6 +156,8 @@ void __init fill_ebus_device(struct device_node *dp, struct linux_ebus_device *d
 	dev->prom_node = dp;
 
 	regs = of_get_property(dp, "reg", &len);
+	if (!regs)
+		len = 0;
 	if (len % sizeof(struct linux_prom_registers)) {
 		prom_printf("UGH: proplen for %s was %d, need multiple of %d\n",
 			    dev->prom_node->name, len,

arch/sparc64/kernel/ebus.c

@@ -375,7 +375,10 @@ static void __init fill_ebus_device(struct device_node *dp, struct linux_ebus_de
 		dev->num_addrs = 0;
 		dev->num_irqs = 0;
 	} else {
-		(void) of_get_property(dp, "reg", &len);
+		const int *regs = of_get_property(dp, "reg", &len);
+
+		if (!regs)
+			len = 0;
 		dev->num_addrs = len / sizeof(struct linux_prom_registers);
 
 		for (i = 0; i < dev->num_addrs; i++)