ASoC: wcd-mbhc: Fix plug type detection with extension cable

When headphone or headset is inserted at the other end of
extension cable, it should be detected correctly and needs
to be reported to the user-space. Update the mbhc driver
to support detection of plug that gets inserted at the other
end of the extension cable.

Change-Id: Ieaed1913479839a73bba21b53e172c249d2fa94a
Signed-off-by: Phani Kumar Uppalapati <phaniu@codeaurora.org>