Add generation of memory usage report of tee.elf
diff --git a/Makefile b/Makefile
index a02d3c2..904735f 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,9 @@
 .PHONY: all
 all:
 
+.PHONY: mem_usage
+mem_usage:
+
 # Make these default for now
 ARCH            ?= arm32
 PLATFORM        ?= stm