mm: fix cma allocation time too long [1/1]

mm: fix cma allocation time too long [1/1]

PD#TV-6340

Problem:
When quickly enter live tv just after boot to home, video may display
more than 10 seconds late after sound comeout. The main problem is
cma allocation time too long.

Solution:
1, add a page flag for pages under cma allocating. And do not
increase page-ref count for cma pages under allocating when it
is used by user space again.
2, restrict shmem/swap back pages using cma
3, improve cma using policy check in page allocating process.
4, replace righ page trace for migrated pages.

Change-Id: Ie6b591213a9eda974c3443ca9b491fa8d00cee50
Signed-off-by: Tao Zeng <tao.zeng@amlogic.com>