[NET]: Fix an off-by-21-or-49 error.

This patch fixes an off-by-21-or-49 error ;-) spotted by the Coverity
checker.
Signed-off-by: NAdrian Bunk <bunk@stusta.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/net-sysfs.c

@@ -165,7 +165,7 @@ static ssize_t show_operstate(struct class_device *dev, char *buf)
 		operstate = IF_OPER_DOWN;
 	read_unlock(&dev_base_lock);
 
-	if (operstate >= sizeof(operstates))
+	if (operstate >= ARRAY_SIZE(operstates))
 		return -EINVAL; /* should not happen */
 
 	return sprintf(buf, "%s\n", operstates[operstate]);