audio: don't reset mixer paths at standby

It's not necessary to reset the mixer paths at standby,
and doing so can cause pops and clicks when the output
path is changed.

In addition, use a more direct path for the headphone
output (avoiding the analogue mixer).

Bug: 7302620
Change-Id: I1741304f65f5c0e05d33eeefdbb3446f4d94119f
2 files changed