ASoC: Intel: Skylake: Fix test of a field address

Skylake driver uses snd_dma_buffer for data and buffer, these are variables
and not pointer so do not test field addresses.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>