Headset: Ability to hang-up a call from a wired audio headset

Address OPO_52.
The KEY_MEDIA and KEY_VOLUMEUP are mapped to multiple buttons.
That will confuse the input class driver when one button is
pressed while others are released. Fuse all buttons with same
function to one will fix the problem.

Change-Id: Ife63602e68d0fad2813821f0c7e0b6d78cc5d878
(cherry picked from commit fd641d9adeec5307f2d6d2dfdd89d6392cc61cd9)