ALSA: hda - Keep pointer to bdl_pos_fix in chip struct

This will allow for a platform hda driver to use it as well.  It
removes the dependency on the module param from hda_intel, which will
allow for azx_setup_periods to be shared.

Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>