ALSA: x86: Use config base depending on the pipe

Now the pipe that is being used is passed over i915 notification, we
can re-setup the relevant register offset depending on pipe assignments
during hotplug.
This allows playback on single port machines such Zotac Pi330 or
dual-port machines such as Dell Wyse 3040 box

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>