USB: qcserial: make probe more flexible

Preparing qcprobe support for more than just strict
Gobi 1k or 2k+ devices.  Many newer Qualcomm based
devices provide the same serial ports, but using
varying USB interface layouts.

Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>