Ensure psock_socket and psock_accept initialize s_crefs to 1

This simplifies the caller usage

fs/nfs/rpc_clnt.c

@@ -408,8 +408,7 @@ int rpcclnt_connect(struct rpcclnt *rpc)
       return errval;
     }
 
-  so->s_crefs     = 1;
-  rpc->rc_so      = so;
+  rpc->rc_so = so;
 
   /* Always set receive timeout to detect server crash and reconnect.
    * Otherwise, we can get stuck in psock_receive forever.

fs/userfs/fs_userfs.c

@@ -1370,8 +1370,6 @@ static int userfs_bind(FAR struct inode *blkdriver, FAR const void *data,
       goto errout_with_alloc;
     }
 
-  priv->psock.s_crefs = 1;
-
   /* Bind the socket to the client address */
 
   client.sin_family      = AF_INET;
@@ -1386,8 +1384,6 @@ static int userfs_bind(FAR struct inode *blkdriver, FAR const void *data,
       goto errout_with_psock;
     }
 
-  priv->psock.s_crefs = 1;
-
   /* Mounted! */
 
   *handle = (FAR void *)priv;