HID: logitech-hidpp: retrieve the HID++ device name when available

hidpp->name can't be null.
Only HID++ 2.0 and above device supports the query.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Tested-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>