pinctrl: mvebu: Add support for MV98DX1135

The 98DX1135 is a switch chip with an integrated CPU. This is similar to
the 98DX4122 except the MPP assignments differ.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>