docs: add Measured Boot design

Added design document for Measured Boot implementation in
TF-A.

Change-Id: I25b57ec555b289eb6bbf0a6aae014d7bf6d152fd
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/docs/resources/diagrams/Makefile b/docs/resources/diagrams/Makefile
index c951754..faf9634 100644
--- a/docs/resources/diagrams/Makefile
+++ b/docs/resources/diagrams/Makefile
@@ -79,7 +79,13 @@
 FWU-update_struct_layers		= "background"
 FWU-update_struct_opts			=
 
-all:$(RESET_PNGS) $(INT_PNGS) $(XLAT_PNG) $(RMM_PNG) $(RMM_EL3_MANIFEST_PNG) $(PSA_FWU_PNG)
+MB_DESIGN_DIA				= measured_boot_design.dia
+MB_DESIGN_PNG				= measured_boot_design.png
+
+measured_boot_design_layers		= "background"
+measured_boot_design_opts		=
+
+all:$(RESET_PNGS) $(INT_PNGS) $(XLAT_PNG) $(RMM_PNG) $(RMM_EL3_MANIFEST_PNG) $(PSA_FWU_PNG) $(MB_DESIGN_PNG)
 
 $(RESET_PNGS):$(RESET_DIA)
 	$(call generate_image,$($(patsubst %.png,%_layers,$@)),$@,png,$($(patsubst %.png,%_opts,$@)),$<)
@@ -99,3 +105,6 @@
 
 $(PSA_FWU_PNG):$(PSA_FWU_DIA)
 	$(call generate_image,$($(patsubst %.png,%_layers,$@)),$@,png,$($(patsubst %.png,%_opts,$@)),$<)
+
+$(MB_DESIGN_PNG):$(MB_DESIGN_DIA)
+	$(call generate_image,$($(patsubst %.png,%_layers,$@)),$@,png,$($(patsubst %.png,%_opts,$@)),$<)