mm, page_alloc: convert alloc_flags to unsigned

alloc_flags is a bitmask of flags but it is signed which does not
necessarily generate the best code depending on the compiler.  Even
without an impact, it makes more sense that this be unsigned.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/internal.h b/mm/internal.h
index 098a89e..114593a 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -175,7 +175,7 @@
 	bool direct_compaction;		/* False from kcompactd or /proc/... */
 	int order;			/* order a direct compactor needs */
 	const gfp_t gfp_mask;		/* gfp mask of a direct compactor */
-	const int alloc_flags;		/* alloc flags of a direct compactor */
+	const unsigned int alloc_flags;	/* alloc flags of a direct compactor */
 	const int classzone_idx;	/* zone index of a direct compactor */
 	struct zone *zone;
 	int contended;			/* Signal need_sched() or lock