We have too many Intel-specific codes in patch_hdmi_generic() despite
its function name.  And this makes it difficult to adjust per chipset,
e.g. for allowing the audio notifier on an old chipset, one would need
to add an explicit if() check.

This patch attempts some code refactoring and cleanups in this regard;
the Intel-specific codes are moved out of patch_generic_hdmi() into
the new functions, patch_i915_hsw_hdmi() and patch_i915_byt_hdmi(),
depending on the chipset.  The other old Intel chipsets keep using
patch_generic_hdmi() without Intel hacks.  The existing
patch_generic_hdmi() is also split to a few components so that they
can be called from the Intel codec parsers.

There are still many is_haswell*() and is_valleyview*() macro usages
in the code.  They will be cleaned up later.  For the time being, only
the entry are concerned.

Along with this change, the i915_bound flag and the on-demand i915
component binding have been removed as a cleanup, since there is no
user at this moment.  This will be added back later once when Cougar
Point and else start using the i915 eld notifier.
Signed-off-by: Takashi Iwai <tiwai@suse.de>