soc-core sets the snd_soc_pcm_runtime->dev drvdata to
snd_soc_pcm_runtime in soc_post_component_init, and access
it in places like codec_reg_show.

hsw_pcm_open overwrites the drvdata to point to hsw_pcm_data,
confusing soc-core, and causing crashes when cat
/sys/devices/pci0000:00/INT3438:00/.../System PCM/codec_reg

This patch removes the set in hsw_pcm_open since it's no longer
used. commit 7ff9d671 ("ASoC: Intel: Split hsw_pcm_data for
playback and capture") already removed all calls to
snd_soc_pcm_get_drvdata(rtd).
Signed-off-by: Ben Zhang <benzh@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>