pinctrl: mvebu: Fix i2c sda definition for 98DX3236

Per the datasheet the i2c functions use MPP_Sel=0x1. They are documented
as using MPP_Sel=0x4 as well but mixing 0x1 and 0x4 is clearly wrong. On
the board tested 0x4 resulted in a non-functioning i2c bus so stick with
0x1 which works.

Fixes: d7ae8f8d

 ("pinctrl: mvebu: pinctrl driver for 98DX3236 SoC")
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20200907211712.9697-2-chris.packham@alliedtelesis.co.nz
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>