With the previous reviews, the page lock is no longer required in order
to perform queue operations on a page.  It is also no longer needed in
the page queue scans.  This change effectively eliminates remaining uses
of the page lock and also the false sharing caused by multiple pages
sharing a page lock.

Reviewed by:	jeff
Tested by:	pho
Sponsored by:	Netflix, Intel
Differential Revision:	https://reviews.freebsd.org/D22885