Add mynewt testplan

Signed-off-by: Fabio Utzig <utzig@apache.org>
diff --git a/testplan/mynewt/key_ec256.pem b/testplan/mynewt/key_ec256.pem
new file mode 100644
index 0000000..0f9264f
--- /dev/null
+++ b/testplan/mynewt/key_ec256.pem
@@ -0,0 +1,5 @@
+-----BEGIN EC PRIVATE KEY-----
+MHcCAQEEINtq7Uc92lGcI9pcfwU7IEWfjtYKMpG3iSLy8vdn3p0poAoGCCqGSM49
+AwEHoUQDQgAEbmhhf9fiyT20CixtsNDO/lS4lq38YIeJQektIcg+HV7Dd/1iX7v7
+2hCnWiOq/AG13HM9N8FFj5A7Zv0rlWacyQ==
+-----END EC PRIVATE KEY-----