ASoC: qcom: sc7180: initialize the "no_headphone" variable

The "no_headphone" variable is never set to "false" so it could be
uninitialized.

Fixes: e936619b ("ASoC: qcom: sc7180: Modify machine driver for sound card")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20201116125950.GA44063@mwanda


Signed-off-by: Mark Brown <broonie@kernel.org>