ALSA: hda - remove controller dependency on i915 power well for Baytrail/Braswell

For Baytrail (Valleyview) and Braswell (Cherryview), only the HDMI codec is
in the display power well while the HD-A controller isn't. So the controller
flag 'need_i915_power' is not set to release the display power after probe,
and the codec flag 'link_power_control" is set to request/release the display
power via bus link_power ops.

Signed-off-by: Mengdong Lin <mengdong.lin@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>