Option to silence informational output

[jpds]

Hello,

I'm trying to create a prometheus.io exporter for opcm, starting with specifically pcm-memory.x.

It'd be good to have a option to silence this bit of the output:

 Processor Counter Monitor: Memory Bandwidth Monitoring Utility  ($Format:%ci ID=%h$)

 This utility measures memory bandwidth per channel or per DIMM rank in real-time

Number of physical cores: 32
Number of logical cores: 64
Number of online logical cores: 64
Threads (logical cores) per physical core: 2
Num sockets: 2
Physical cores per socket: 16
Core PMU (perfmon) version: 4
Number of core PMU generic (programmable) counters: 4
Width of generic (programmable) counters: 48 bits
Number of core PMU fixed counters: 3
Width of fixed counters: 48 bits
Nominal core frequency: 2100000000 Hz
Package thermal spec power: 125 Watt; Package minimum power: 69 Watt; Package maximum power: 264 Watt; 
Socket 0: 2 memory controllers detected with total number of 6 channels. 3 QPI ports detected.
Socket 1: 2 memory controllers detected with total number of 6 channels. 3 QPI ports detected.

[jpds]

I've found that I can do this by using 2>/dev/null, but it'd be nicer to have this as a command line flag.

[opcm]

Implemented 2de1a80