Asoc: wcd: mbhc: Force lineout event report only for headphone

Correct plug type to lineout only if headphone is detected and
impedance of left and right is above 5000 ohm. This avoids reporting
lineout for valid headset devices like tty.

CRs-Fixed: 899726
Change-Id: I048c5e63e8cdd526fecf20211f061ed61db39522
Signed-off-by: Walter Yang <yandongy@codeaurora.org>