ANDROID: mm: Create vendor hooks to control ZONE_MOVABLE allocations

Create a vendor hook inside of gfp_zone() to modify which allocations
get to enter ZONE_MOVABLE, by zeroing out __GFP_HIGHMEM inside of the
trace hook based on certain conditions.

Separately, create separate trace hooks in the swap-in and readahead
paths to affect the behavior of the tracehook in gfp_zone().

Bug: 158645321
Change-Id: I4a4f0b724267ee120a1e5661f6da5d43d7ef6fc6
Signed-off-by: Chris Goldsworthy <cgoldswo@codeaurora.org>