arm64: tegra: Add node for Tegra234 CCPLEX cluster

Adding CCPLEX cluster node to represent Tegra234 cpufreq. Tegra234 uses
some of the CRAB (Control Register Access Bus) registers for CPU
frequency requests. These registers are memory mapped to the
CCPLEX_MMCRAB_ARM region. In this node, mapping the range of MMCRAB
registers is required only for CPU frequency info.

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