s390: simplify one level sysctl registration for cmm_table

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

Simplify this registration.
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Link: https://lore.kernel.org/r/20230310234525.3986352-5-mcgrof@kernel.orgReviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/mm/cmm.c

@@ -335,16 +335,6 @@ static struct ctl_table cmm_table[] = {
 	{ }
 };
 
-static struct ctl_table cmm_dir_table[] = {
-	{
-		.procname	= "vm",
-		.maxlen		= 0,
-		.mode		= 0555,
-		.child		= cmm_table,
-	},
-	{ }
-};
-
 #ifdef CONFIG_CMM_IUCV
 #define SMSG_PREFIX "CMM"
 static void cmm_smsg_target(const char *from, char *msg)
@@ -389,7 +379,7 @@ static int __init cmm_init(void)
 {
 	int rc = -ENOMEM;
 
-	cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
+	cmm_sysctl_header = register_sysctl("vm", cmm_table);
 	if (!cmm_sysctl_header)
 		goto out_sysctl;
 #ifdef CONFIG_CMM_IUCV