scsi: libiscsi: Move ehwait initialization to iscsi_session_setup()

scsi: libiscsi: Move ehwait initialization to iscsi_session_setup()

Commit bd3d031216c2 ("scsi: iscsi: Fix conn use after free during resets")
moved member ehwait from 'conn' to 'session', but left the initialization
of ehwait in iscsi_conn_setup().

Although a session can only have 1 conn currently, it is better to
initialize ehwait in iscsi_session_setup() in case we implement handling
multiple conns in the future.

Link: https://lore.kernel.org/r/20210911135159.20543-1-dinghui@sangfor.com.cn
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Ding Hui <dinghui@sangfor.com.cn>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>