Async link event provides port_speed info. Cache the port_speed info
and use the same to report in ISCSI_HOST_PARAM_PORT_SPEED query.

Removed link status query IOCTL used to do the same.
Signed-off-by: Jitendra Bhivare <jitendra.bhivare@avagotech.com>
Reviewed-by: Hannes Reinicke <hare@suse.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>