ASoC: Fix build failure in soc-core.c

ASoC: Fix build failure in soc-core.c

Commit 2eea392 "ASoC: Add support for optional auxiliary dailess codecs"
causes a build failure in soc-core.c: soc_probe_aux_dev since code tries to
access non-existing struct snd_soc_dapm_context and struct snd_soc_card
members.

Root cause for this was a double accident. Author sent the RFC patch from
top of another patch set and the RFC got committed. Fix the build failure
by removing the code line that depends on that another patch set.

Signed-off-by: Jarkko Nikula <jhnikula@gmail.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>