mm: hugetlb_vmemmap: fix CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON

The following:

commit 47010c040dec ("mm: hugetlb_vmemmap: cleanup CONFIG_HUGETLB_PAGE_FREE_VMEMMAP*")

forgot to update CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON used in
vmemmap_optimize_mode to CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON.
The result is we cannot enable hugetlb_optimize_vmemmap at boot time when
we configure CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON. Fix it.

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: 47010c040dec ("mm: hugetlb_vmemmap: cleanup CONFIG_HUGETLB_PAGE_FREE_VMEMMAP*")
Signed-off-by: Muchun Song <[e-mail]>
Reported-by: Vlastimil Babka <[e-mail]>
Acked-by: Vlastimil Babka <[e-mail]>
Cc: Mike Kravetz <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

mm/hugetlb_vmemmap.c

···
 EXPORT_SYMBOL(hugetlb_optimize_vmemmap_key);
 
 static enum vmemmap_optimize_mode vmemmap_optimize_mode =
-	IS_ENABLED(CONFIG_HUGETLB_PAGE_FREE_VMEMMAP_DEFAULT_ON);
+	IS_ENABLED(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON);
 
 static void vmemmap_optimize_mode_switch(enum vmemmap_optimize_mode to)
 {