usbfs: Allow printer class 'get_device_id' without needing to claim the intf

usbfs: Allow printer class 'get_device_id' without needing to claim the intf

For certain (HP) printers the printer device_id does not only contain a
static part identifying the printer, but it also contains a dynamic part
giving printer status, ink level, etc.

To get to this info various userspace utilities need to be able to make a
printer class 'get_device_id' request without first claiming the interface
(as that is in use for the actual printer driver).

Since the printer class 'get_device_id' request does not change interface
settings in anyway, allowing this without claiming the interface should not
cause any issues.

CC: Sanjay Kumar <sanjay.kumar14@hp.com>
CC: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>