mm, oom: pass an oom order of -1 when triggered by sysrq

The force_kill member of struct oom_control isn't needed if an order of -1
is used instead.  This is the same as order == -1 in struct
compact_control which requires full memory compaction.

This patch introduces no functional change.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/memcontrol.c

@@ -1550,7 +1550,6 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
 		.nodemask = NULL,
 		.gfp_mask = gfp_mask,
 		.order = order,
-		.force_kill = false,
 	};
 	struct mem_cgroup *iter;
 	unsigned long chosen_points = 0;