ALSA: hda - Allow i915 binding later in codec driver

Due to the recent change, HDA controller driver for Intel PCH tries to
bind i915 audio component always at the probe time no matter whether
HDMI/DP codec is found.  This is, however, superflulous for old
chipsets (e.g. on IVB) where they don't have always the HDMI/DP codecs
but  often have only a discrete GPU instead.

For the newer chipsets, we need already the i915 binding from the
beginning due to power well control.  Meanwhile, for older chipsets
where we don't need power well, we don't need the i915 binding at the
controller level.

This patch removes again the i915 binding in the HDA controller driver
for old Intel PCHs, but adds the binding in HDMI/DP codec driver
instead.  This allows still the use of the direct notification from
the graphics driver while we can avoid the unnecessary load of i915
driver for machines only with another GPU.

Signed-off-by: Takashi Iwai <tiwai@suse.de>