ASoC: Intel: avs: Implement PCI shutdown

On shutdown reference to i915 driver needs to be released to not spam
logs with unnecessary warnings. While at it do some additional cleanup
to make sure DSP is powered down and interrupts from device are
disabled.

Fixes: 1affc44e

 ("ASoC: Intel: avs: PCI driver implementation")
Reported-by: Kornel Dulęba <korneld@google.com>
Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski@linux.intel.com>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20230113190310.1451693-2-amadeuszx.slawinski@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>