device_test: improve handling of avtka_ui
device_test: improve handling of avtka_ui

Allows the Avtka based UIs running with the device_test binary
to show off the same LED status as the hardware.

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

openAVproductions/openAV-Ctlra