net: Remove redundant assignment to err

Variable 'err' is set to -ENOMEM but this value is never read as it is
overwritten with a new value later on, hence the 'If statements' and
assignments are redundantand and can be removed.

Cleans up the following clang-analyzer warning:

net/ipv6/seg6.c:126:4: warning: Value stored to 'err' is never read
[clang-analyzer-deadcode.DeadStores]
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/seg6.c

@@ -122,9 +122,6 @@ static int seg6_genl_sethmac(struct sk_buff *skb, struct genl_info *info)
 	hinfo = seg6_hmac_info_lookup(net, hmackeyid);
 
 	if (!slen) {
-		if (!hinfo)
-			err = -ENOENT;
-
 		err = seg6_hmac_info_del(net, hmackeyid);
 
 		goto out_unlock;