mm: compaction: use helper isolation_suitable()

Use helper isolation_suitable() to check whether page is suitable to
isolate to simplify the code.  Minor readability improvement.

Link: https://lkml.kernel.org/r/20220322110750.60311-1-linmiaohe@huawei.comSigned-off-by: NMiaohe Lin <linmiaohe@huawei.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NWei Yang <richard.weiyang@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

mm/compaction.c

@@ -899,7 +899,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		 * not falsely conclude that the block should be skipped.
 		 */
 		if (!valid_page && IS_ALIGNED(low_pfn, pageblock_nr_pages)) {
-			if (!cc->ignore_skip_hint && get_pageblock_skip(page)) {
+			if (!isolation_suitable(cc, page)) {
 				low_pfn = end_pfn;
 				page = NULL;
 				goto isolate_abort;