ASoC: intel: incorrect sizeof()

This should be sizeof(pos) instead of sizeof(&pos).  Most likely they
are both 8 bytes though so it doesn't often make a difference in real
life.

Fixes: 22981243 ('ASoC: Intel: Add Haswell/Broadwell IPC')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>