Add vid/pid table to umb(4) allowing matching to alternate config

Add vid/pid table to umb(4) allowing matching to alternate config

Some devices present multiple configurations and the one chosen by default
is not always usable - for example, some have an CDC ECM config that does
not work with our cdce(4) - allow overriding to a specific config in those
cases.

From gerhard@ with tweaks to comments by me, ok patrick@