CHERRY-PICK: UPSTREAM: HID: Fix logitech-dj: missing Unifying device issue

CHERRY-PICK: UPSTREAM: HID: Fix logitech-dj: missing Unifying device issue

This patch fixes an issue introduced after commit 4ea5454203d991ec
("HID: Fix race condition between driver core and ll-driver").

After that commit, hid-core discards any incoming packet that arrives while
hid driver's probe function is being executed.

This broke the enumeration process of hid-logitech-dj, that must receive
control packets in-band with the mouse and keyboard packets. Discarding mouse
or keyboard data at the very begining is usually fine, but it is not the case
for control packets.

This patch forces a re-enumeration of the paired devices when a packet arrives
that comes from an unknown device.

Based on a patch originally written by Benjamin Tissoires.

BUG=chromium-os:39354
TEST=manually tested on Link

(cherry picked from upstream commit 596264082f10dd4a567c43d4526b2f54ac5520bc)
Change-Id: I03408c97bb295599306ec74e55698076d5112f81
Cc: stable@vger.kernel.org   # v3.2+
Signed-off-by: Nestor Lopez Casado <nlopezcasad@logitech.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Reviewed-on: https://gerrit.chromium.org/gerrit/46003
Reviewed-by: Yufeng Shen <miletus@chromium.org>
Commit-Queue: Andrew de los Reyes <adlr@chromium.org>
Tested-by: Andrew de los Reyes <adlr@chromium.org>