ASoC: samsung: odroid: Add support for secondary CPU DAI

This patch adds DPCM links in order to support the secondary I2S interface.
For the secondary PCM interface to be actually available one more entry
should be added to the sound-dai property in sound/cpu node in DT.
The changes in driver are done in a way so we are backwards compatible
with existing DTS/DTB, i.e. if the cpu sound-dai property contains only
one entry only one PCM will be registered.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>