usblp: quirk flag and device entry for Seiko Epson M129C printer

This patch (as872) adds a device table entry and a new quirk flag to
the usblp driver for the Seiko Epson Receipt printer.  This printer
returns Vendor-Specific values for bInterfaceClass and
bInterfaceSubClass, but the bInterfaceProtocol value is valid and it
works with usblp.  The new quirks flag tells the driver to ignore the
Class and SubClass values in the interface descriptor.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>