ANDROID: mm: page_pinner refactoring

Currently, page_pinner code are too ugly since we missed refactoring
last time due to GKI deadline. Let's make it better this time before
GKI is freezing.

What this patch is cleaning are __reset_page_pinner which is used
for freeing page as well as putting pages depending on free parameter.
It makes code too ugly for readability PoV and hard to make further
changes so split it with each put and free functions.

Bug: 218731671
Signed-off-by: Minchan Kim <minchan@google.com>
Change-Id: I610ffc629eea5e996b7d55340b5589a3f49574d7