ASoC: Define API to find a dai link

Define the API to find an existing DAI link of the soc card by matching
the ID, name and stream name.

Some cards may use unique ID for each DAI link, so matching ID is enough,
and name or stream name are not necessary. But user need to specify name
or stream name as well if not sure whether link ID is unique since most
cards use 0 as the default link ID.

Topology can use this API to find an existing BE link and configure it.

Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>