USB: ftdi_sio: enable two UART ports on ST Microconnect Lite

commit 71d9a2b95fc9c9474d46d764336efd7a5a805555 upstream.

The FT4232H used in the ST Micro Connect Lite has four hi-speed UART ports.
The first two ports are reserved for the JTAG interface.

We enable by default ports 2 and 3 as UARTs (where port 2 is a
conventional RS-232 UART)

Signed-off-by: Adrian Thomasset <adrian.thomasset@st.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>