ASoC: fix the building issue of missing codec field in 'struct snd_soc_card'

[Mark Brown]

On Tue, Nov 02, 2010 at 05:10:07AM +0800, Eric Miao wrote:

Applied but please provide a signoff and remember to CC both Liam and
alsa-devel for ASoC patches.  I've taken it without the signoff since
it's a small and obvious fix.