devmatch: introduce quiet command line option

[bz]

Summary

In setups without hints whatsoever one can get a long list of
"Can't read linker hints file" error messages during boot.
Add a -q/--quiet option which would suppress the noise and leave
space for more essential information.

While here switch to a pre-defined exit code from sysexits.

MFC after: 4 weeks

[imp]

I'd add this to the devd rule... but not the rc.d script. That will give one error on boot.

[bz]

In D41443#943747, @imp wrote:

I'd add this to the devd rule... but not the rc.d script. That will give one error on boot.

Thanks. I'll have a look. I hadn't planned to activate it by default in main yet but if there's the easy good way, then that's probably the way to go :)