BugLink: http://bugs.launchpad.net/bugs/1531539

Remove the calculation of all the bits written into the CC register into
nvme_enable_ctrl, so that they can be moved into the core NVMe driver in
the future.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
(cherry picked from commit 1b2eb374)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>