qahw: test: Use module id 0x10940 for DTMF event testing

Change the playback test to use Module ID 0x10940
for event testing with DTMF instead of 0x10EEC.
0x10940 is a new DTMF module used specifically for
the audio path.

Change-Id: Iaf54bab1fcf8426941d43002f774d67b5a7fea64