nfs: update for module_param_named API change

After merging the rr tree, today's linux-next build (powerpc
ppc64_defconfig) failed like this:

net/sunrpc/auth.c:74: error: 'param_ops_hashtbl_sz' undeclared here (not in a function)

Caused by commit 0685652df0929cec7d78efa85127f6eb34962132
("param:param_ops") interacting with commit
f8f853ab19fcc415b6eadd273373edc424916212 ("SUNRPC: Make the credential
cache hashtable size configurable") from the nfs tree.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

net/sunrpc/auth.c

@@ -39,7 +39,7 @@ static LIST_HEAD(cred_unused);
 static unsigned long number_cred_unused;
 
 #define MAX_HASHTABLE_BITS (10) 
-static int param_set_hashtbl_sz(const char *val, struct kernel_param *kp)
+static int param_set_hashtbl_sz(const char *val, const struct kernel_param *kp)
 {
 	unsigned long num;
 	unsigned int nbits;
@@ -61,7 +61,7 @@ static int param_set_hashtbl_sz(const char *val, struct kernel_param *kp)
 	return -EINVAL;
 }
 
-static int param_get_hashtbl_sz(char *buffer, struct kernel_param *kp)
+static int param_get_hashtbl_sz(char *buffer, const struct kernel_param *kp)
 {
 	unsigned int nbits;
 
@@ -71,6 +71,11 @@ static int param_get_hashtbl_sz(char *buffer, struct kernel_param *kp)
 
 #define param_check_hashtbl_sz(name, p) __param_check(name, p, unsigned int);
 
+static struct kernel_param_ops param_ops_hashtbl_sz = {
+	.set = param_set_hashtbl_sz,
+	.get = param_get_hashtbl_sz,
+};
+
 module_param_named(auth_hashtable_size, auth_hashbits, hashtbl_sz, 0644);
 MODULE_PARM_DESC(auth_hashtable_size, "RPC credential cache hashtable size");