ASoC: qdsp6: q6asm-dai: do not close port if its not opened

asm ports are open as part of prepare, so for use cases like
"aplay sample.wav" were sample.wav is not present. This would
call port close eventhough port was never opened. DSP would
return errors for such use cases.

Avoid doing this by checking the port state.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Mark Brown <broonie@kernel.org>