[SERIAL] sunsu: Handle keyboard and mouse ports directly.

[SERIAL] sunsu: Handle keyboard and mouse ports directly.

The sunsu_ports[] array exists merely to be able to easily
use an integer index to get at the proper serial console
port struct.

We size this only for real ports, not for the keyboard and
mouse, and thus keyboard and mouse port registration would
fail.

Fix this by dynamically allocating the port struct for the
keyboard and mouse, instead of using the sunsu_ports[]
array.

Signed-off-by: David S. Miller <davem@davemloft.net>