soc/tegra: Add initial flowctrl support for Tegra132/210

soc/tegra: Add initial flowctrl support for Tegra132/210

Tegra132 and Tegra210 support the flowctrl module and so add initial
support for these devices.

Please note that Tegra186 does not support the flowctrl module, so
update the initialisation function such that we do not fall back and
attempt to map the 'hardcoded' address range for Tegra186. Furthermore
64-bit Tegra devices have always had the flowctrl node defined in their
device-tree and so only use the 'hardcoded' addresses for 32-bit Tegra
devices.

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