ASoC: mdm9615: Add headset detection through mechanical switch

Use mechanical switch on the phone jack to detect headset/headphone
insertion and removal.  Mechanical switch is beneficial to avoid fake
button press and high impedance microphone headset detection.
Both top and bottom speakers are controlled by GPIO 5 and GPIO 3 is
used for HS Detection.

Change-Id: I8a78b1181f0e32360daebd57d6ea0f9e45b46221
Signed-off-by: Shiv Maliyappanahalli <smaliyap@codeaurora.org>