mm/page_alloc: explicitly record high-order atomic allocations in alloc_flags

mm/page_alloc: explicitly record high-order atomic allocations in alloc_flags

A high-order ALLOC_HARDER allocation is assumed to be atomic.  While that
is accurate, it changes later in the series.  In preparation, explicitly
record high-order atomic allocations in gfp_to_alloc_flags().

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Mel Gorman <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: NeilBrown <[email protected]>
Cc: Thierry Reding <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>