Staging: rt2870: new device id

Hey, I have an Edimax wireless USB adapter that uses the rt2870 chipset.
lsusb shows it as follows:

Bus 001 Device 002: ID 7392:7717

When I added that ID to rt2870.h, the device came up and worked as
expected.

From: Dave Hayes <dwhayes@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>