scsi: lpfc: Fix removal of SCSI transport device get and put on dev structure

The lpfc driver is calling get_device and put_device on scsi_fc_transport
device structure. When this code was removed, the driver triggered an oops
in "scsi_is_host_dev" when the first SCSI target was unregistered from the
transport.

The reason the calls were necessary is that the driver is calling
scsi_remove_host too early, before the target rports are unregistered and
the scsi devices disconnected from the scsi_host.  The fc_host was torn
down during fc_remove_host.

Fix by moving the lpfc_pci_remove_one_s3/s4 calls to scsi_remove_host to
after the nodes are cleaned up.  Remove the get_device and put_device calls
and the supporting code.

Link: https://lore.kernel.org/r/20201115192646.12977-4-james.smart@broadcom.com
Co-developed-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: Dick Kennedy <dick.kennedy@broadcom.com>
Signed-off-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>