nfsd: remove unused macro in nfsv4

lk_rflags is never used anywhere, and rflags is not defined in struct
nfsd4_lock.
Signed-off-by: NYanchuan Nian <ycnian@gmail.com>
Signed-off-by: NJ. Bruce Fields <bfields@redhat.com>

fs/nfsd/xdr4.h

@@ -184,7 +184,6 @@ struct nfsd4_lock {
 #define lk_old_lock_stateid     v.old.lock_stateid
 #define lk_old_lock_seqid       v.old.lock_seqid
 
-#define lk_rflags       u.ok.rflags
 #define lk_resp_stateid u.ok.stateid
 #define lk_denied       u.denied