cmhw: only expose userspace options if kernel supports it

Change-Id: I16e62b3a4b01f906db228fe84a32ec546c7a320e
m8: Increase the volume step at which the safe volume warning shows

Currently the warning shows up at less than half volume, at normal
listening volume. This bumps it up a bit.

Change-Id: Ie85bb036f75a55b2eb6d1802baba11e632c19908