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>

net/sunrpc/auth_gss/gss_rpc_upcall.c

@@ -63,7 +63,7 @@ enum {
 	.p_name   = #proc,				\
 }
 
-static struct rpc_procinfo gssp_procedures[] = {
+static const struct rpc_procinfo gssp_procedures[] = {
 	PROC(INDICATE_MECHS, indicate_mechs),
         PROC(GET_CALL_CONTEXT, get_call_context),
         PROC(IMPORT_AND_CANON_NAME, import_and_canon_name),