ASoC: Intel: Skylake: Fix dma buffer size calculation

DMA buffer size for gateway copier will be calculated based on:

For host DMA copier:
Input buffer size (ibs) for output direction (playback)
Output buffer size (obs) for input direction (capture)

For link DMA copier:
IBS for input direction (capture)
OBS for output direction (playback)

Update the driver to use the above.

Signed-off-by: Ramesh Babu <ramesh.babu@intel.com>
Signed-off-by: Subhransu S. Prusty <subhransu.s.prusty@intel.com>
Acked-By: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>