sc7180: Add qdsp based soundcard

Merge series from Nikita Travkin <nikita@trvn.ru>:

Some devices, such as Acer Aspire 1, can't use lpass dirrectly, but
instead must use adsp core to play sound. Since otherwise the hardware
is, usually, very similar across the devices on the same platform, it
makes sense to reuse the same boardfile.

This series refactors the sc7180.c slightly and adds the functions to
control clocks via adsp instead of controlling the hardware directly.