USB: serial: option: Add support for Quectel EP06

The Quectel EP06 is a Cat. 6 LTE modem, and the interface mapping is as
follows:

0: Diag
1: NMEA
2: AT
3: Modem

Interface 4 is QMI and interface 5 is ADB, so they are blacklisted.

This patch should also be considered for -stable. The QMI-patch for this
modem is already in the -stable-queue.

v1->v2:
* Updated commit prefix (thanks Johan Hovold)
* Updated commit message slightly.

Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>