Controllers must have buttons and a movement mechanism.

Some devices have joystick axes or DPad keys, but no gamepad buttons
(or vice versa). We shouldn't count these as gamepads since games
can't really be expected to work with this setup in the general case.
Instead, require that a device has a movement mechanism (joystick
axes or DPad buttons), as well as at least one gamepad button before
considering it a controller.

Bug: 13432364
Change-Id: Ia113c8441557d4c858c1e5740a3e1c7e0e9fdcdd