NFS: Use RPC functions for matching sockaddrs

They already exist and do the exact same thing.  Let's save ourselves
several lines of code!

Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c
index 3aa6a9b..223bedd 100644
--- a/fs/nfs/nfs4client.c
+++ b/fs/nfs/nfs4client.c
@@ -729,10 +729,7 @@
 		return false;
 
 	/* Match only the IP address, not the port number */
-	if (!nfs_sockaddr_match_ipaddr(addr, clap))
-		return false;
-
-	return true;
+	return rpc_cmp_addr(addr, clap);
 }
 
 /*