feat(tc): add DPE context handle node to device tree

Child software components are inheriting their first valid
DPE context handle from their parent components (who loaded
and measured them). The context handle is shared through
the device tree object the following way:
 - BL1 -> BL2  via TB_FW_CONFIG
 - BL2 -> BL33 via NT_FW_CONFIG

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: I9bf7808fb13a310ad7ca1895674a0c7e6725e08b
8 files changed