scsi: qedi: Fix TMF session block/unblock use

scsi: qedi: Fix TMF session block/unblock use

BugLink: https://bugs.launchpad.net/bugs/1939738
[ Upstream commit 2819b4ae2873d50fd55292877b0231ec936c3b2e ]

Drivers shouldn't be calling block/unblock session for tmf handling because
the functions can change the session state from under libiscsi.
iscsi_queuecommand's call to iscsi_prep_scsi_cmd_pdu->
iscsi_check_tmf_restrictions will prevent new cmds from being sent to qedi
after we've started handling a TMF. So we don't need to try and block it in
the driver, and we can remove these block calls.

Link: https://lore.kernel.org/r/20210525181821.7617-25-michael.christie@oracle.com
Reviewed-by: Manish Rangankar <mrangankar@marvell.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>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>