Correct help text of target configs
Correct help text of target configs

The config options target_prefix, target_ip_address,
iscsi_secondary_ip_addresses, target_port are common for both
iSCSI and NVMEoF targets.
This patch updates the help text to reflect the same.

Change-Id: I4b46da01824823adae5127bed1531b7024291644

mahak/cinder,mahak/cinder,openstack/cinder,openstack/cinder