nvme: Call pci_disable_device on the error path.

BugLink: http://bugs.launchpad.net/bugs/1628520

Commit 5706aca74fe4 ("NVMe: Don't unmap controller registers on reset"),
which backported b00a726a to the 4.4.y kernel introduced a
regression in which it didn't call pci_disable_device in the error path
of nvme_pci_enable.
Reported-by: Jiri Slaby <jslaby@suse.cz>
Embarassed-developer: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from linux-stable commit 81e9a969)
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>

drivers/nvme/host/pci.c

@@ -1772,7 +1772,7 @@ static int nvme_pci_enable(struct nvme_dev *dev)
 	return 0;
 
  disable:
-	pci_release_regions(pdev);
+	pci_disable_device(pdev);
 
 	return result;
 }