mm, compaction: remove unnecessary zone parameter in some instances

mm, compaction: remove unnecessary zone parameter in some instances

A zone parameter is passed into a number of top-level compaction
functions despite the fact that it's already in compact_control.  This
is harmless but it did need an audit to check if zone actually ever
changes meaningfully.  This patches removes the parameter in a number of
top-level functions.  The change could be much deeper but this was
enough to briefly clarify the flow.

No functional change.

Link: http://lkml.kernel.org/r/20190118175136.31341-5-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>