nvme-pci: Fix an error handling path in 'nvme_probe()'

Release resources in the correct order in order not to miss a
'put_device()' if 'nvme_dev_map()' fails.

Fixes: b00a726a ("NVMe: Don't unmap controller registers on reset")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>