USB: cdc-acm: Remove Motorola/Telit H24 serial interfaces from ACM driver

By specifying NO_UNION_NORMAL the ACM driver does only use the first two
USB interfaces (modem data & control). The AT Port, Diagnostic and NMEA
interfaces are left to the USB serial driver.

Signed-off-by: Michael Ulbricht <michael.ulbricht@systec-electronic.com>
Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>