mm: hugetlb_vmemmap: simplify hugetlb_vmemmap_init() a bit

The check of IS_ENABLED(CONFIG_PROC_SYSCTL) is unnecessary since
register_sysctl_init() will be empty in this case.  So, there is no
warnings after removing the check.

Link: https://lkml.kernel.org/r/20230223065947.64134-1-songmuchun@bytedance.comSigned-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/hugetlb_vmemmap.c

@@ -590,17 +590,15 @@ static struct ctl_table hugetlb_vmemmap_sysctls[] = {
 
 static int __init hugetlb_vmemmap_init(void)
 {
+	const struct hstate *h;
+
 	/* HUGETLB_VMEMMAP_RESERVE_SIZE should cover all used struct pages */
 	BUILD_BUG_ON(__NR_USED_SUBPAGE * sizeof(struct page) > HUGETLB_VMEMMAP_RESERVE_SIZE);
 
-	if (IS_ENABLED(CONFIG_PROC_SYSCTL)) {
-		const struct hstate *h;
-
-		for_each_hstate(h) {
-			if (hugetlb_vmemmap_optimizable(h)) {
-				register_sysctl_init("vm", hugetlb_vmemmap_sysctls);
-				break;
-			}
+	for_each_hstate(h) {
+		if (hugetlb_vmemmap_optimizable(h)) {
+			register_sysctl_init("vm", hugetlb_vmemmap_sysctls);
+			break;
 		}
 	}
 	return 0;