sunrpc: mark all struct rpc_procinfo instances as const

struct rpc_procinfo contains function pointers, and marking it as
constant avoids it being able to be used as an attach vector for
code injections.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Trond Myklebust <trond.myklebust@primarydata.com>
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 40cf552..0f1f290 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -7594,7 +7594,7 @@ nfs4_stat_to_errno(int stat)
 	.p_name = #proc,	\
 }
 
-struct rpc_procinfo	nfs4_procedures[] = {
+const struct rpc_procinfo nfs4_procedures[] = {
 	PROC(READ,		enc_read,		dec_read),
 	PROC(WRITE,		enc_write,		dec_write),
 	PROC(COMMIT,		enc_commit,		dec_commit),