Separate DAI link and aux dev initialization in preparation for
DAI multicodec support.
Since aux dev will remain using single codecs but DAI links
will be able to support multiple codecs.

No functional change.
Signed-off-by: NMisael Lopez Cruz <misael.lopez@ti.com>
[fparent@baylibre.com: Adapt to 3.14+]
Signed-off-by: NFabien Parent <fparent@baylibre.com>
Signed-off-by: NBenoit Cousson <bcousson@baylibre.com>
Signed-off-by: NMark Brown <broonie@linaro.org>