mm/thp: simplify has_transparent_hugepage by using IS_BUILTIN

Simplify code of has_transparent_hugepage define by using IS_BUILTIN.

No functional change.

Link: https://lkml.kernel.org/r/20220829095709.3287462-1-liushixin2@huawei.comSigned-off-by: NLiu Shixin <liushixin2@huawei.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

include/linux/pgtable.h

@@ -1598,11 +1598,7 @@ typedef unsigned int pgtbl_mod_mask;
 #endif
 
 #ifndef has_transparent_hugepage
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-#define has_transparent_hugepage() 1
-#else
-#define has_transparent_hugepage() 0
-#endif
+#define has_transparent_hugepage() IS_BUILTIN(CONFIG_TRANSPARENT_HUGEPAGE)
 #endif
 
 /*