SUNRPC: display human-readable procedure name in rpc_iostats output

Add fields to the rpc_procinfo struct that allow the display of a
human-readable name for each procedure in the rpc_iostats output.

Also fix it so that the NFSv4 stats are broken up correctly by
sub-procedure number.  NFSv4 uses only two real RPC procedures:
NULL, and COMPOUND.

Test plan:
Mount with NFSv2, NFSv3, and NFSv4, and do "cat /proc/self/mountstats".

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/mount_clnt.c b/fs/nfs/mount_clnt.c
index db99b8f..4a13403 100644
--- a/fs/nfs/mount_clnt.c
+++ b/fs/nfs/mount_clnt.c
@@ -137,6 +137,8 @@
 	  .p_encode		= (kxdrproc_t) xdr_encode_dirpath,	
 	  .p_decode		= (kxdrproc_t) xdr_decode_fhstatus,
 	  .p_bufsiz		= MNT_dirpath_sz << 2,
+	  .p_statidx		= MNTPROC_MNT,
+	  .p_name		= "MOUNT",
 	},
 };
 
@@ -146,6 +148,8 @@
 	  .p_encode		= (kxdrproc_t) xdr_encode_dirpath,
 	  .p_decode		= (kxdrproc_t) xdr_decode_fhstatus3,
 	  .p_bufsiz		= MNT_dirpath_sz << 2,
+	  .p_statidx		= MOUNTPROC3_MNT,
+	  .p_name		= "MOUNT",
 	},
 };