net: af_mpls.c add space before open parenthesis

Adding space after switch keyword before open
parenthesis for readability purpose.

This patch fixes the checkpatch.pl warning:
space required before the open parenthesis '('
Signed-off-by: NSuraj Deshmukh <surajssd009005@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/mpls/af_mpls.c

@@ -1252,7 +1252,7 @@ static int rtm_to_route_config(struct sk_buff *skb,  struct nlmsghdr *nlh,
 		if (!nla)
 			continue;
 
-		switch(index) {
+		switch (index) {
 		case RTA_OIF:
 			cfg->rc_ifindex = nla_get_u32(nla);
 			break;