arm64: tegra: Separate AON pinmux from main pinmux on Tegra194

The registers for the AON pinmux reside in a partition different from
the registers for the main pinmux. Instead of treating them as one and
the same device, split them up so that they are each their own devices.
Also add gpio-ranges properties to the corresponding GPIO controllers
such that the pinmux and GPIO controllers can be paired up properly.

Signed-off-by: Thierry Reding <treding@nvidia.com>