Currently, if a class can not be merged, the max objects of zspage in
that class may be calculated twice.

This patch calculate max objects of zspage at the begin, and pass the
value to can_merge() to decide whether the class can be merged.

Also this patch remove function get_maxobj_per_zspage(), as there is no
other place to call this function.

Link: http://lkml.kernel.org/r/1467882338-4300-4-git-send-email-opensource.ganesh@gmail.comSigned-off-by: NGanesh Mahendran <opensource.ganesh@gmail.com>
Reviewed-by: NSergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>