mm/zswap: invalidate duplicate entry when !zswap_enabled

We have to invalidate any duplicate entry even when !zswap_enabled since
zswap can be disabled anytime.  If the folio store success before, then
got dirtied again but zswap disabled, we won't invalidate the old
duplicate entry in the zswap_store().  So later lru writeback may
overwrite the new data in swapfile.

Link: https://lkml.kernel.org/r/20240208023254.3873823-1-chengming.zhou@linux.dev
Fixes: 42c06a0e

 ("mm: kill frontswap")
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>