ASoC: mbhc-adc: Prevent lineout from being reported two times

Sometimes lineout is reported twice, first during initial
detection and then during loop due to output mic voltage
not being measured correctly. Prevent cable from being
reported as headphone during second time if it was reported
as lineout in initial detection.

Change-Id: If828917cb2acbb0ed5b2de9bf1431d0fbb4a9d10
Signed-off-by: Vatsal Bucha <vbucha@codeaurora.org>