ASoC: Intel: avs: Refactor IRQ handling

Merge series from Cezary Rojewski <cezary.rojewski@intel.com>:

The existing code can be both improved and simplified. To make this
change easier to manage, first add new implementation and then remove
deadcode in a separate patch.

Simplification achieved with:

- reduce the amount of resources requested by the driver i.e.: IPC and
  CLDMA request_irq() merged into one
- reduce the number of DSP ops from 2 to 1:
  irq_handler/thread() vs dsp_interrupt()
- drop ambiguity around CLDMA interrupt, let skl.c handle that
  explicitly as it is the only user

With that done, switch to the new implementation and remove unused
members. While the change is non-trivial, from functional perspective
status quo is achieved.