There is a bug where a device with index 6 would write out of bounds in
the array of paired devices.
This patch fixes that problem.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Reviewed-by: Olivier Gay <ogay@logitech.com>
Signed-off-by: Nestor Lopez Casado <nlopezcasad@logitech.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

With this driver, all the devices paired to a single Unifying
receiver are exposed to user processes in separated /input/dev
nodes.

Keyboards with different layouts can be treated differently,
Multiplayer games on single PC (like home theater PC) can
differentiate input coming from different kbds paired to the
same receiver.

Up to now, when Logitech Unifying receivers are connected to a
Linux based system, a single keyboard and a single mouse are
presented to the HID Layer, even if the Unifying receiver can
pair up to six compatible devices. The Unifying receiver by default
multiplexes all incoming events (from multiple keyboards/mice)
into these two.

Signed-off-by: Nestor Lopez Casado <nlopezcasad@logitech.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>