zsmalloc: make zspage chain size configurable

Remove hard coded limit on the maximum number of physical pages
per-zspage.

This will allow tuning of zsmalloc pool as zspage chain size changes
`pages per-zspage` and `objects per-zspage` characteristics of size
classes which also affects size classes clustering (the way size classes
are merged).

Link: https://lkml.kernel.org/r/20230118005210.2814763-4-senozhatsky@chromium.org


Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Minchan Kim <minchan@kernel.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>