net/pkt: Fix coverity issue

The value ret is overwritten after being assigned a value.

Signed-off-by: zhangshuai39 <zhangshuai39@xiaomi.com>

net/pkt/pkt_recvmsg.c

@@ -499,7 +499,7 @@ ssize_t pkt_recvmsg(FAR struct socket *psock, FAR struct msghdr *msg,
   if (psock->s_type != SOCK_DGRAM && psock->s_type != SOCK_RAW)
     {
       nerr("ERROR: Unsupported socket type: %d\n", psock->s_type);
-      ret = -ENOSYS;
+      return -ENOSYS;
     }
 
   /* Get the device driver that will service this transfer */