scsi: iscsi: Move iscsi_ep_disconnect()

scsi: iscsi: Move iscsi_ep_disconnect()

[ Upstream commit c34f95e98d8fb750eefd4f3fe58b4f8b5e89253b ]

This patch moves iscsi_ep_disconnect() so it can be called earlier in the
next patch.

Link: https://lore.kernel.org/r/20220408001314.5014-2-michael.christie@oracle.com
Tested-by: Manish Rangankar <mrangankar@marvell.com>
Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Chris Leech <cleech@redhat.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>