Just make the code responsible for possible_in > 0 also handle
possible_in == 0 since it nearly does the same thing.
The only difference is that the possible_in == 0 case, by using
FOUNDCFG(), acted as if possible_in was audio_in. The consolidated code
uses FOUNDCFG_IMPRECISE which will add some penalty to the
configurations where desired_in == possible_in != audio_in.
There is thus a small POLICY CHANGE, but the selected configuration will
stay the same unless a better matching configuration is available.