Dynamic cfg: Enable support on CoT for other configs

This patch implements support for adding dynamic configurations for
BL31 (soc_fw_config), BL32 (tos_fw_config) and BL33 (nt_fw_config). The
necessary cert tool support and changes to default chain of trust are made
for these configs.

Change-Id: I25f266277b5b5501a196d2f2f79639d838794518
Signed-off-by: Soby Mathew <soby.mathew@arm.com>