Add basic Kbuild support for the Tegra SoC family, and specifically,
the Tegra132 SoC.  Tegra132 pairs the NVIDIA Denver CPU complex with
the SoC integration of Tegra124 - hence the use of ARCH_TEGRA and the
Tegra124 pinctrl option.

This patch was based on a patch originally written by Allen Martin
<amartin@nvidia.com>.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Paul Walmsley <pwalmsley@nvidia.com>
Cc: Allen Martin <amartin@nvidia.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>