nvme: Add nvme_core.force_apst to ignore the NO_APST quirk

We're probably going to be stuck quirking APST off on an over-broad
range of devices for 4.11.  Let's make it easy to override the quirk
for testing.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>