mbedtls-amis: Checkout code from TF repo

Checkout code from TF repo[1]

[1]: https://git.trustedfirmware.org/next/ci/mbedtls-amis.git

Signed-off-by: Arthur She <arthur.she@linaro.org>
Change-Id: I754554aed36bc079af3f35dc061893becda3a9a9
diff --git a/mbedtls-amis/builders.sh b/mbedtls-amis/builders.sh
index fe84b93..be49110 100644
--- a/mbedtls-amis/builders.sh
+++ b/mbedtls-amis/builders.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 
 rm -rf mbedtls-amis
-git clone https://gitlab.com/suihkulokki/mbedtls-amis.git
+git clone https://git.trustedfirmware.org/next/ci/mbedtls-amis.git
 cd mbedtls-amis
 
 packer build packer_config.json