NFSD:fix boolreturn.cocci warning

./fs/nfsd/nfssvc.c: 1072: 8-9: :WARNING return of 0/1 in function
'nfssvc_decode_voidarg' with return type bool

Return statements in functions returning bool should use true/false
instead of 1/0.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: Changcheng Deng <deng.changcheng@zte.com.cn>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfssvc.c

@@ -1069,7 +1069,7 @@ int nfsd_dispatch(struct svc_rqst *rqstp, __be32 *statp)
  */
 bool nfssvc_decode_voidarg(struct svc_rqst *rqstp, struct xdr_stream *xdr)
 {
-	return 1;
+	return true;
 }
 
 /**