nvme: move to a new drivers/nvme/host directory

This patch moves the NVMe driver from drivers/block/ to its own new
drivers/nvme/host/ directory.  This is in preparation of splitting the
current monolithic driver up and add support for the upcoming NVMe
over Fabrics standard.  The drivers/nvme/host/ is chose to leave space
for a NVMe target implementation in addition to this host side driver.

Signed-off-by: Jay Sternberg <[email protected]>
[hch: rebased, renamed core.c to pci.c, slight tweaks]
Signed-off-by: Christoph Hellwig <[email protected]>
Acked-by: Keith Busch <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
12 files changed