mm/zswap: remove zswap_entry_cache_{create,destroy} helper function

Patch series "Delay the initialization of zswap", v9.

In the initialization of zswap, about 18MB memory will be allocated for
zswap_pool.  Since some users may not use zswap, the zswap_pool is wasted.
Save memory by delaying the initialization of zswap until enabled.


This patch (of 3):

Remove zswap_entry_cache_create and zswap_entry_cache_destroy and use
kmem_cache_* function directly.

Link: https://lkml.kernel.org/r/20230411093632.822290-1-liushixin2@huawei.com
Link: https://lkml.kernel.org/r/20230403121318.1876082-1-liushixin2@huawei.com
Link: https://lkml.kernel.org/r/20230403121318.1876082-2-liushixin2@huawei.com


Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>