ASoC: Fix snd_soc_register_dais error handling

kzalloc for dai may fail at any iteration of the for loop,
thus properly unregister already registered DAIs before return error.

The error handling code in snd_soc_register_dais() already ensure all the DAIs
are unregistered before return error, we can remove the error handling code
to unregister DAIs in snd_soc_register_codec().

Signed-off-by: Axel Lin <axel.lin@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>