Have dissect_usb_setup_request handle non-standard requests

Moved code for parsing non-standard setup requests from
dissect_usb_common() to dissect_usb_setup_request().

Also added header_info flag USB_HEADER_IS_MAUSB & updated mausb
dissector.

Change-Id: Ifa8abccbd57bf4dd3965f582872952383e6f737d
Reviewed-on: https://code.wireshark.org/review/3851
Petri-Dish: Anders Broman <a.broman58@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>