sunrpc: move p_count out of struct rpc_procinfo

p_count is the only writeable memeber of struct rpc_procinfo, which is
a good candidate to be const-ified as it contains function pointers.

This patch moves it into out out struct rpc_procinfo, and into a
separate writable array that is pointed to by struct rpc_version and
indexed by p_statidx.

Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 797f3ce..40cf552 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -7661,10 +7661,12 @@
 #endif /* CONFIG_NFS_V4_2 */
 };
 
+static unsigned int nfs_version4_counts[ARRAY_SIZE(nfs4_procedures)];
 const struct rpc_version nfs_version4 = {
 	.number			= 4,
 	.nrprocs		= ARRAY_SIZE(nfs4_procedures),
-	.procs			= nfs4_procedures
+	.procs			= nfs4_procedures,
+	.counts			= nfs_version4_counts,
 };
 
 /*