ASoC: wcd9310: Fix incorrect detection while slow headphone insertion

- If a headphone is inserted slowly, on gpio connection headphone
  detected and correct plug work is scheduled to identify if a
  headset is detected as headphone incorrectly. While correct plug
  detection, sometimes it gets detected as unsupported plug type
  which results in reporting of headphone removal and insertion of
  unsupported plug type.
- Correct the plug type detection logic to skip further voltage
  measurement if any of the first two measurements are invalid
  and to update the plug_type only if it is valid detection.

Change-Id: I64bac25f6230fc6486b9e327f396b06be438f061
CRs-fixed: 390835
Signed-off-by: Ravi Kumar Alamanda <ralama@codeaurora.org>