ARM: tegra: pinctrl: move Tegra210 code to the correct dir

ARM: tegra: pinctrl: move Tegra210 code to the correct dir

Patches that added the Tegra210 pinctrl driver and renamed directories
arch/arm/cpu/tegra{$soc}-common -> arch/arm/mach-tegra/tegra-${soc}
crossed. Move the Tegra210 pinctrl driver to the correct location. This
wasn't detected since Tegra210 support is in the process of being added,
and isn't buildable yet.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>