ASoC: soc-topology: fix modern dai link style

The topology code can create a FE DAI link but did not allocate the
memory for a platform component - whose name can be overridden at a
later time.

Fixes: 23b946ce

 ("ASoC: soc-topology: use modern dai_link style")
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>