ASoC: atmel: Don't squash error codes from atmel_ssc_set_audio()

The AT91SAM9G20-EK audio driver is replacing any error code returned by
atmel_ssc_set_audio() with -EINVAL which could be unhelpful for debugging.
Pass through the error code, and include it in the log message we print for
good measure.

Signed-off-by: Mark Brown <broonie@kernel.org>