feat(tc): add DPE backend to the measured boot framework

The client platform relies on the DICE attestation
scheme. RSS provides the DICE Protection Environment
(DPE) service. TF-A measured boot framework supports
multiple backends. A given platform always enables
the corresponding backend which is required by the
attestation scheme.

Signed-off-by: Tamas Ban <tamas.ban@arm.com>
Change-Id: Idc3360d0d7216e4859e99b5db3d377407e0aeee5
diff --git a/Makefile b/Makefile
index ef570b2..800346a 100644
--- a/Makefile
+++ b/Makefile
@@ -1145,6 +1145,7 @@
 	HARDEN_SLS \
 	HW_ASSISTED_COHERENCY \
 	MEASURED_BOOT \
+	DICE_PROTECTION_ENVIRONMENT \
 	DRTM_SUPPORT \
 	NS_TIMER_SWITCH \
 	OVERRIDE_LIBC \
@@ -1312,6 +1313,7 @@
 	HW_ASSISTED_COHERENCY \
 	LOG_LEVEL \
 	MEASURED_BOOT \
+	DICE_PROTECTION_ENVIRONMENT \
 	DRTM_SUPPORT \
 	NS_TIMER_SWITCH \
 	PL011_GENERIC_UART \