ARM: tegra: enable GPU node by compatible value

ARM: tegra: enable GPU node by compatible value

In current Linux kernel Tegra DT files, 64-bit addresses are represented
in unit addresses as a pair of comma-separated 32-bit values. Apparently
this is no longer the correct representation for simple busses, and the
unit address should be represented as a single 64-bit value. If this is
changed in the DTs, arm/arm/mach-tegra/board2.c:ft_system_setup() will no
longer be able to find and enable the GPU node, since it looks up the node
by name.

Fix that function to enable nodes based on their compatible value rather
than their node name. This will work no matter what the node name is, i.e
for DTs both before and after any rename operation.

Cc: Thierry Reding <treding@nvidia.com>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>