ASoC: dapm: Fix double prefix addition

The prefix for the codec driver can be used during dual identical
codec usecases. However, dapm adds prefix twice for codec DAI widget
in snd_soc_dapm_add_route API.

This change is to avoid double prefix addition for codec DAI widget
and is needed while using identical dual codecs.

Signed-off-by: Songhee Baek <sbaek@nvidia.com>
Signed-off-by: Arun Shamanna Lakshmi <aruns@nvidia.com>
Signed-off-by: Mark Brown <broonie@linaro.org>