mm/compaction: remove repeat compact_blockskip_flush check in reset_isolation_suitable

mm/compaction: remove repeat compact_blockskip_flush check in reset_isolation_suitable

We have compact_blockskip_flush check in __reset_isolation_suitable, just
remove repeat check before __reset_isolation_suitable in
compact_blockskip_flush.

Link: https://lkml.kernel.org/r/20230901155141.249860-5-shikemeng@huaweicloud.com
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>