Input: elantech - report the middle button of the touchpad
Input: elantech - report the middle button of the touchpad

In the past, no elantech was known with 3 touchpad mouse buttons.
Fujitsu H730 is the first known elantech with a middle button. This commit
enables this middle button. For backwards compatibility, the Fujitsu is
detected via DMI, and only for this one 3 buttons will be announced.

Reported-by: Stefan Valouch <eb0877843acc39f8ef6f7269937dee931c372d23@valouch.com>
Signed-off-by: Ulrik De Bie <81c0edba6215d5b70a03986af3bc3f0cb4badd11@e2big.org>
Signed-off-by: Dmitry Torokhov <6b8646d310837fed93a129ed3c979b90c7f2674f@gmail.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs