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

commit 895d240d1db0b2736d779200788e4c4aea28a0c6 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>