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

Create a new core.c and start by adding the command submission helpers
to it, which are already abstracted away from the actual hardware queues
by the block layer.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
(back ported from commit 21d34711)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

 Conflicts:
	drivers/nvme/host/Makefile