ASoC: Intel: Remove skylake driver

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

A spiritual successor to haswell/baytrail removal series [1].

The avs-driver found in sound/soc/intel/avs is a direct replacement to
the existing skylake-driver. It covers all features supported by it and
more and aligns with the recommended flows and requirements based on
Windows driver equivalent.

The skylake-driver related UAPI has been removed with "ASoC: Drop
soc-topology ABI v4 support" [2].

For the official kernel tree the deprecation begun with v6.0. Most
skylake-drivers users moved to avs- or SOF-driver when AudioDSP
capabilities are available on the platform or to snd-hda-intel
(sound/pci/hda) when such capabilities are not.

For the supported trees the deprecation begun with v5.4 with v5.15 being
the first where the skylake-driver is disabled entirely.

All machine board drivers that consume this DSP driver have their
replacements present within sound/soc/intel/avs/boards/ directory.

[1]: https://lore.kernel.org/alsa-devel/20201006064907.16277-1-cezary.rojewski@intel.com/
[2]: https://lore.kernel.org/alsa-devel/20240403091629.647267-1-cezary.rojewski@intel.com/

diff --cc MAINTAINERS
Simple merge

diff --cc sound/soc/codecs/cs35l56-shared.c
Simple merge

diff --cc sound/soc/codecs/es8326.c
Simple merge

diff --cc sound/soc/intel/boards/Kconfig
Simple merge

diff --cc sound/soc/intel/boards/Makefile
Simple merge