[ upstream commit 618f0f4a ]

Helps strings syntax is "command : description", the 'command' part was
missing, updated command help strings.

Fixes: 281eeb8a ("app/testpmd: add commands for metering and policing")
Fixes: 30ffb4e6 ("app/testpmd: add commands traffic metering and policing")
Fixes: e63b5016 ("app/testpmd: clean metering and policing commands")

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: Jasvinder Singh <jasvinder.singh@intel.com>
Acked-by: Xiaoyun Li <xiaoyun.li@intel.com>