ASoC: codec2codec: avoid invalid/double-free of pcm runtime

The PCM runtime was freed during PMU in the case that the event hook
encountered an error. However, it is also unconditionally freed during
PMD. Avoid a double-free by dropping the call to kfree in the PMU hook.

Fixes: a72706ed

 ("ASoC: codec2codec: remove ephemeral variables")
Cc: stable@vger.kernel.org
Signed-off-by: Samuel Holland <samuel@sholland.org>
Link: https://lore.kernel.org/r/20200213061147.29386-2-samuel@sholland.org
Signed-off-by: Mark Brown <broonie@kernel.org>