configs: lahaina: fix audio not heard over speaker for haptics

For parsing paths in xml file, libaudioroute will break if
a duplicated ctl is found, this can cause the ctl of audio over
speaker skipped, so for combo device usecases, audio will be
lost on speaker.
Fix it by removing nested path, replace with single mixer ctl
for combo device usecases.

Change-Id: Ibe74ed8ed28b3a5534b8b44edd211b5bb6bb8583