ALSA: hda: move hda_codec.h to include/sound

As suggested by Takashi, move this header file to make it easier
to include from e.g. the Intel Skylake driver in follow-up patches

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>