ARM: Kirkwood: Add pinctrl of TWSI1 to 88f6282

The 88f6282 has one more TWSI(TWSI1). This add the information to enable
pinctl of TWSI1.

Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Acked-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jason Cooper <jason@lakedaemon.net>