Add back tinycrypt Makefiles

Signed-off-by: Fabio Utzig <utzig@apache.org>
diff --git a/ext/tinycrypt/lib/source/Makefile b/ext/tinycrypt/lib/source/Makefile
new file mode 100644
index 0000000..b61b05c
--- /dev/null
+++ b/ext/tinycrypt/lib/source/Makefile
@@ -0,0 +1,4 @@
+# Zephyr makefile.
+# subdir-ccflags-y += -I$(PROJECT)/ext/tinycrypt/lib/include
+
+obj-y += ecc.o ecc_dsa.o sha256.o utils.o
diff --git a/ext/tinycrypt/lib/source/Makefile.inc b/ext/tinycrypt/lib/source/Makefile.inc
new file mode 100644
index 0000000..ebb101a
--- /dev/null
+++ b/ext/tinycrypt/lib/source/Makefile.inc
@@ -0,0 +1,3 @@
+# vim: ft=make
+
+subdir-ccflags-$(NEED_TINYCRYPT) += -I$(PROJECT)/ext/tinycrypt/lib/include