The lookup of CPU and CODEC DAIs is fairly similar and can easily be
consolidated into a single helper function.

There are two main differences in the current implementation of the CPU and
CODEC DAI lookup:
 1) CPU DAIs can be looked up by the DAI name alone and do not necessarily
   require a component name/of_node.
 2) The CODEC DAI search only considers DAIs from CODEC components.

For 1) the new helper function will allow to lookup DAIs without providing a
component name or of_node, but since snd_soc_register_card() already rejects
CODEC DAI link components without neither a of_node or a name we'll never get
into the situation where we try to lookup a CODEC DAI without a name/of_node.
For 2) the new helper function just always considers all components.
Componentization is now at a point where it is possible to register a CODEC as a
snd_soc_component rather than a snd_soc_codec, by considering DAIs from all
components it is possible to use such a CODEC in a DAI link.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>