This is the only node we are interested in so do not waste time to test
creating device that will be either unused or fail as most of the nodes
don't have a compatible string.
Add pinctrl driver for RockChip SoCs. This device manage which function
to set on which pin and some other properties like pull up/down, drive
strength etc ...
For now the driver only support RK3328 but it is versatile enough to
add support for other RockChip SoC in the future.
