ASoC: wm8904: Remove unnecessary call to snd_soc_dapm_new_widgets()

The core will call snd_soc_dapm_new_widgets() once all components of the card
have been initialized, so there is no need to do this manually in the driver.
Calling it earlier also might result in a partially instantiated system being
powered up which cause undesired side effects.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>