hid-logitech-dj.c driver needs hidraw to work correctly. Without
hidraw, hid-logitech-dj.c fails during probe() and Logitech
Unifying devices HID reports aren't recognized.

The unifying receiver has 3 usb interfaces. When hid-logitech-dj driver is
loaded, interfaces 0 and 1 are discarded.

Interface 2 consists of a hid class interface with 3 collections, each of
which sports the 'vendor' usage, thus, there is no reason for hid_input to
claim any of them. On the other hand, hidraw has no issue in claiming the
collections, even if they are 'vendor'. As of today, hid-logitech-dj uses
hidraw api to send configuration/control reports to interface 2 of the
Unifying receiver.

Without the hid-logitech-dj driver, interfaces 0 and 1 are claimed by
hid-input, as they correspond to a keyboard and a mouse. But that is not
relevant to the discussion.

[jkosina@suse.cz: make the changelog more verbose, thanks to Nestor]
Signed-off-by: Olivier Gay <ogay@logitech.com>
Signed-off-by: Nestor Lopez Casado <nlopezcasad@logitech.com>
Signed-off-by: Mathieu Meisser <mmeisser@logitech.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>