nfs: simplify two-level sysctl registration for nfs4_cb_sysctls

There is no need to declare two tables to just create directories,
this can be easily be done with a prefix path with register_sysctl().

Simplify this registration.

Reviewed-by: Jeff Layton <[e-mail]>
Signed-off-by: Luis Chamberlain <[e-mail]>

fs/nfs/nfs4sysctl.c

···
 	{ }
 };
 
-static struct ctl_table nfs4_cb_sysctl_dir[] = {
-	{
-		.procname = "nfs",
-		.mode = 0555,
-		.child = nfs4_cb_sysctls,
-	},
-	{ }
-};
-
-static struct ctl_table nfs4_cb_sysctl_root[] = {
-	{
-		.procname = "fs",
-		.mode = 0555,
-		.child = nfs4_cb_sysctl_dir,
-	},
-	{ }
-};
-
 int nfs4_register_sysctl(void)
 {
-	nfs4_callback_sysctl_table = register_sysctl_table(nfs4_cb_sysctl_root);
+	nfs4_callback_sysctl_table = register_sysctl("fs/nfs",
+						     nfs4_cb_sysctls);
 	if (nfs4_callback_sysctl_table == NULL)
 		return -ENOMEM;
 	return 0;