Adapt kettenis' pinctrl changes in imx to sitaracm and

Adapt kettenis' pinctrl changes in imx to sitaracm and
pinctrl-single,pins to handle mux settings and pad configuration.

The fdt data has offsets from the start of the pinmux address range so
the am335x specific pinmux offset from the scm base is added to the
offsets.  This as not a new driver as sitaracm does manual table
driven pad configuration for gpio.  If all the offsets in the
ti_padconf_devmap table were reduced by the am335x pinmux offset (0x800)
it may make sense to map only the pinmux memory region and not the
scm superset.

looks good kettenis@