Fix minor issues in dmux default impl

Test: mannual
Change-Id: If74df110cd9eda2dadb87a8d659d83233ad75d88
(cherry picked from commit 9a1e5aa93a17037bfef8cf8d8e156042ca2c814e)
Merged-In: If74df110cd9eda2dadb87a8d659d83233ad75d88
1 file changed