At the moment, OP-TEE has no support to receive a DTB in Secure Memory
so it cannot receive TOS_FW_CONFIG_ID as it is supposed to happen on
any BL32 image. Instead, when OP-TEE is enable as BL32 payload,
NT_FW_CONFIG_ID is passed.

This MUST be reverted as soon as OP-TEE has support for receiving
DTBs from Secure Memory.

Change-Id: I9a873f42e94f2f99a60b638333e7afba1505aec9
Signed-off-by: Javier Almansa Sobrino <javier.almansasobrino@arm.com>