ASoC: fix memory leak

If dai_link is already bound then we just returned and leaked rtd and
rtd->codec_dais which were allocated by soc_new_pcm_runtime(). We do not
need this newly allocated rtd to check if dai_link is already binded. Lets
check first if it is already binded before allocating this memory.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Mark Brown <broonie@kernel.org>