feat(tc): share DPE context handle with child component

To be allowed to communicate with DPE service all
components must own a valid context handle. The first
valid context handle is inherited from the parent
component via a DTB object.

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: Id357fab3586398b1933444e1d10d1ab6d8243ab9
diff --git a/drivers/measured_boot/rss/dice_prot_env.c b/drivers/measured_boot/rss/dice_prot_env.c
index 6417cdc..67b51a9 100644
--- a/drivers/measured_boot/rss/dice_prot_env.c
+++ b/drivers/measured_boot/rss/dice_prot_env.c
@@ -130,7 +130,7 @@
 			 */
 			VERBOSE("Share new_context_handle with child: 0x%x\n",
 				new_context_handle);
-			/* TODO: share context handle */
+			plat_dpe_share_context_handle(&new_context_handle);
 		}
 	} else {
 		ERROR("dpe_derive_context failed: %d\n", ret);