FIX: [droid] do not package non-standard joystick keymap

Ref: http://forum.xbmc.org/showthread.php?tid=173413&pid=1551731#pid1551731

Apparently, on non-droid platforms, the buttons and axises number change from joystick to joystick, while they are fixed at OS level in droid.
Result is that using, e.g., a PS3 gamepad, on droid doesn't work because the buttons number are wrong.

All droid needs is the default map, so do not pack the others.

/cc @davilla @garbear