USB: serial: qcserial: add Dell DW5811e

commit 436ecf5519d892397af133a79ccd38a17c25fa51 upstream.

This is a Dell branded Sierra Wireless EM7455.

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