Parametrize mcp_docker_registry host

Related-Bug: PROD-22480 (PROD:22480)

Change-Id: I36ad55a1960f6c8e025d9c967bbc7658927fc872
diff --git a/jenkins/client/job/k8s-test/mcp-k8s-merge-pipeline.yml b/jenkins/client/job/k8s-test/mcp-k8s-merge-pipeline.yml
index f209aa2..e7697a0 100644
--- a/jenkins/client/job/k8s-test/mcp-k8s-merge-pipeline.yml
+++ b/jenkins/client/job/k8s-test/mcp-k8s-merge-pipeline.yml
@@ -1,4 +1,6 @@
 parameters:
+  _param:
+    mcp_docker_registry: 'docker-dev-local.docker.mirantis.net'
   jenkins:
     client:
       job:
@@ -32,5 +34,5 @@
           param:
             KUBE_DOCKER_REGISTRY:
               type: string
-              default: 'docker-dev-local.docker.mirantis.net'
+              default: ${_param:mcp_docker_registry}
               description: 'Docker registry for binaries and images'