Add support for Telit LE910C1-EUX composition

0x1031: tty, tty, tty, rmnet
Signed-off-by: Daniele Palmas <dnlplm@gmail.com>
Acked-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: David S. Miller <davem@davemloft.net>