The Logitech M560 is a wireless mouse designed for windows 8 which uses
the unifying receiver.
Compared to a standard one, some buttons (the middle one and the
two ones placed on the side) are bound to a key combination
instead of a generating classic "mouse" button events.

The device shows up as a mouse and keyboard combination: when the middle
button is pressed it sends a key (as keyboard) combination, the same
happens for the two side button. The left/right/wheel work as expected
from a mouse. To complicate things further, the middle button sends
different keys combinations between odd and even presses.
In the "even" press it also sends a left click. But the worst thing
is that no event is generated when the middle button is released.

It is possible to re-configure the mouse sending a command (see function
m560_send_config_command()). After this command the mouse sends some
useful data when the buttons are pressed and/or released.

[jkosina@suse.cz: fix build breakage due to leftover from previous
 patch version]
Signed-off-by: Goffredo Baroncelli <kreijack@inwind.it>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>