dev_test: don't accept generic MIDI device
dev_test: don't accept generic MIDI device

Makes no sense to test a generic MIDI implementation, as the
implementation is generic. Ignoring it allows the next driver
to create the AVTKA UI - so that this example still serves its
purpose.

Signed-off-by: Harry van Haaren <6e1296516ee88185cd60d9725251227ece1af74d@gmail.com>

openAVproductions/openAV-Ctlra