qmi_wwan: do not steal interfaces from class drivers

The USB_DEVICE_INTERFACE_NUMBER matching macro assumes that
the { vendorid, productid, interfacenumber } set uniquely
identifies one specific function.  This has proven to fail
for some configurable devices. One example is the Quectel
EM06/EP06 where the same interface number can be either
QMI or MBIM, without the device ID changing either.

Fix by requiring the vendor-specific class for interface number
based matching.  Functions of other classes can and should use
class based matching instead.

Fixes: 03304bcb ("net: qmi_wwan: use fixed interface number matching")
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>