DMA Position in Buffer (DPIB) should be used for
ring buffer management, while LPIB register provides
information on the number of samples transfered on
the link. The difference between the two pieces of
information corresponds to hardware/DMA buffering.

This patch reports this difference in runtime->delay, and
removes the use of the COMBO mode on recent Intel hardware.

Credits to Takashi Iwai for an initial patch.

[rebased to for-next branch and replaced snd_printk() with
 snd_printdd() by tiwai]
Signed-off-by: NPierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>