Platforms that do not support bpmp firmware, do not need access
to the PMC block from outside of the CPU complex. The agents
running on the CPU can always access the PMC through the EL3
exception space.

This patch restricts non-secure world access to the PMC block on
such platforms.

Change-Id: I2c4318dc07ddf6407c1700595e0f4aac377ba258
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>