ANDROID: add vendor_hook to control CMA allocation ratio

CMA first allocation policy for movable makes CMA(Upstream doesn't)
area always full. It's good for memory efficiency since it could use
up CMA available memory most of time. However, it could cause
cma_alloc slow since it causes a lot page migration all the time.

Let's add vendor hook for someone who want to restore CMA allocation
policy to upstream so they will see less page migration in cma_alloc.

If the vendor_hook returns false, the rmqueue_bulk return 0 without
filling pcp->lists so get_populated_pcp_list will return NULL.
Once get_populated_pcp_list returns NULL, __rmqueue_pcplist will retry
the page allocation with original migratetype(currently, original
migratetype couldn't be MIGRATE_CMA) so the retrial will find
available pages from !MIGRATE_CMA free list.

Bug: 231978523
Signed-off-by: Minchan Kim <minchan@google.com>
Change-Id: Ia031d9bc6f34085b892a8d9923bf5b9b1794f94a