Switch to Mbed-TLS/mbedtls.git and Mbed-TLS/mbedtls-test.git

mbedtls.git and mbedtls-test.git have been moved to under https://github.com/Mbed-TLS
So, modify jobs accordingly.

Signed-off-by: Arthur She <arthur.she@linaro.org>
Change-Id: Ifb2d1b8794482c22b3d70a1a5125d35c864db501
diff --git a/mbedtls-dockerfile-builder.yaml b/mbedtls-dockerfile-builder.yaml
index 1ea8bd6..6057f0a 100644
--- a/mbedtls-dockerfile-builder.yaml
+++ b/mbedtls-dockerfile-builder.yaml
@@ -72,7 +72,7 @@
     name: mbedtls-dockerfile-builder
     parameters:
     - string:
-        default: https://github.com/ARMmbed/mbedtls-test
+        default: https://github.com/Mbed-TLS/mbedtls-test.git
         description: Enter mbed TLS test repo/fork
         name: MBED_TLS_TEST_REPO
         trim: 'false'