ASoC: samsung: odroid: Ensure proper sample rate on pri/sec PCM

Currently when playing sound with different sample rates actual
sample rate will be determined by audio stream which starts first
on either primary or secondary PCM. The audio root clock will be
configured appropriately only for the first stream. As the hardware
is limited to same sample rate on both interfaces we need to disallow
streams with different sample rates. It is done by this patch by
returning error in FE hw_params if there is already active stream
running with different sample rate.

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