ethtool: remove unnecessary check in ethtool_get_regs()

We recently changed this function in commit f9fc54d3 ("ethtool:
check the return value of get_regs_len") such that if "reglen" is zero
we return directly.  That means we can remove this condition as well.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/ethtool.c

@@ -1348,12 +1348,9 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr)
 	if (regs.len > reglen)
 		regs.len = reglen;
 
-	regbuf = NULL;
-	if (reglen) {
-		regbuf = vzalloc(reglen);
-		if (!regbuf)
-			return -ENOMEM;
-	}
+	regbuf = vzalloc(reglen);
+	if (!regbuf)
+		return -ENOMEM;
 
 	ops->get_regs(dev, &regs, regbuf);