ASoC: wcd9xxx: Update valid delta threshold when plug type is HIGH_HPH

Whenever plug type is classified as HIGH_HPH during successive DCE
measurements, it is observed that the difference min and max measured
mic voltage will be above 10mv for a current source. Update this valid
threshold limit to 80mv so that plug type cannot be classified as invalid.

CRs-fixed: 566579
Change-Id: I0a87ad58161646f4c94da601a8ec6ffc3f1b06c8
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>