ANDROID: vendor_hooks: Add hooks for adjusting alloc_flags

In some situations, we want to adjust the alloc_flags for better performance.

more detail explain:
the reason why we add a vendor hook adjusting alloc_flags:
1 the user only pass parameter size and gfp_flags once. if we mask the
__GFP_RECLAIM, we can't distinguish high-order and low-order, they all
will not rise reclaim behavior, it's wrong.

2 for __iommu_dma_alloc_pages, there is a loop to try to alloc pages from
high-order to low-order fallback, and we add hook callsite to only change
the high-order( > costly order) alloc behavior(which high probability will
result more overhead than benifit).
which allow low order alloc to do reclaim behavior still, otherwise may
end up with alloc fail.

3 in android ION(drivers/dma-buf/heaps/system_heap.c )
there is same logic, high-order alloc will not do reclaim behavior.

so this change add a vendor hook for adjusting alloc_flags, and add a
callsite in __iommu_dma_alloc_pages to turn the reclaim behavior.

Bug: 300857012
Change-Id: I30bd634d8ede1cc29c83d52bdd9276c8cf72ac1e
Signed-off-by: lvwenhuan <lvwenhuan@oppo.com>
Signed-off-by: liwei <liwei1234@oppo.com>
(cherry picked from commit d6c24c3a)