lockd: Remove unused typedef

Clean up: Looks like the last usage of this typedef was removed by
commit 026fec7 ("sunrpc: properly type pc_decode callbacks") in
2017.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: NeilBrown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: chucklever

include/linux/lockd/xdr.h

@@ -73,8 +73,6 @@ struct nlm_args {
 	u32			fsm_mode;
 };
 
-typedef struct nlm_args nlm_args;
-
 /*
  * Generic lockd result
  */