ALSA: hda - Improved position reporting on SKL+

Apply the same methods to obtain the current stream position as ASoC
Intel SKL driver uses.  It reads the position from DPIB for a playback
stream while it still reads from the position buffer for a capture
stream.  For a capture stream, some ugly workaround is needed to
settle down the inconsistent position.

Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>