The non secure world would like to profile the boot path for
the EL3 and S-EL1 firmwares. To allow it to do that, a non-secure
DRAM region (4K) is allocated and the base address is passed to
the EL3 firmware.

This patch adds a library to allow the platform code to store the
tag:timestamp pair to the shared memory. The tegra platform code
then uses the `record` method to add timestamps.

Original change by Akshay Sharan <asharan@nvidia.com>

Change-Id: Idbbef9c83ed84a508b04d85a6637775960dc94ba
Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>