ASoC: Intel: avs: 16 channels support

ASoC: Intel: avs: 16 channels support

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

Relatively small delta-wise patchset which raises max channels supported
from 8 to 16.  The existing limitation is software-based, not hardware
based.  The hardware, as per HDAudio specification, section 1.2.2,
(relevant register at SDnFMT, section 3.3.41) supports the
configurations for years.  The avs-driver becomes the first consumer of
that configuration on the Linux kernel side.

Set starts off with update to string_helpers so that functionality added
with parse_int_array_user() can be utilized in kernel-kernel
interactions.

Follow up is rasing the cap on HDAudio-library side.  The format
selection procedure found in the library is good-to-go as is.

Everything that follows these two patches is avs-driver specific:
- raise channels_max for every DAI-driver template
- provide i2s_test module parameter for testing purposes.  When combined
  with I2S loopback card, allows to test 16ch on most Intel hardware post
  Broadwell era
- adjust TDM masks to reflect the 8 -> 16 channels change