ARM: dts: Add i2c0 pinctrl information for 98dx3236

Add pinctrl information for the 98dx3236 (and variants). There is only
one choice for i2c0 MPP14 and MPP15.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>