HID: waltop: Add support for Waltop Q Pad

Add support for Waltop Q Pad by fixing its report descriptor.

This tablet is also sold as Aiptek HyperPen Mini. Other possible names
include: NGS Flexi Style, VisTablet PenPad, iVistaTablet Q Flex Pad, Bravod
Q-PD65-S.

Signed-off-by: Nikolai Kondrashov <spbnick@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>