ASoC: jack: Remove unnecessary call to snd_soc_dapm_new_widgets()

snd_soc_jack_add_pins() does not create any new DAPM widgets, so there is no
need to call snd_soc_dapm_new_widgets().

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