sunrpc: move pc_count out of struct svc_procinfo

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

This patch moves it into out out struct svc_procinfo, and into a
separate writable array that is pointed to by struct svc_version.

Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index aa643a2..6452592 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1261,7 +1261,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 	svc_putnl(resv, RPC_SUCCESS);
 
 	/* Bump per-procedure stats counter */
-	procp->pc_count++;
+	versp->vs_count[proc]++;
 
 	/* Initialize storage for argp and resp */
 	memset(rqstp->rq_argp, 0, procp->pc_argsize);