USB HID: add support for dynamically-created quirks

Add internal support for dynamically-allocated HID quirks, "dquirks"
(for "dynamic quirks").  Includes several functions to add/modify quirks
from the list.  This code is used by the next patch to implement quirk
modification upon module load.

Signed-off-by: Paul Walmsley <paul@booyaka.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>