Use system variable for ECR repository

ECR repositories are stored in system variables. Use this
so that CI can work parellly to the one in upstream.

Change-Id: Id75bb5a49305a7abc059741f8bcb4e60595fbf1a
Signed-off-by: Saheer Babu <saheer.babu@arm.com>
diff --git a/misra-docker-images/builders.sh b/misra-docker-images/builders.sh
index cdd89ce..c4bbffd 100755
--- a/misra-docker-images/builders.sh
+++ b/misra-docker-images/builders.sh
@@ -14,12 +14,12 @@
 cd misra-dockerfiles
 
 aws configure list
-export ECR=987685672616.dkr.ecr.us-east-1.amazonaws.com
+export ECR=${PRIVATE_CONTAINER_REGISTRY}
 # we are expecting private files to be kept in the dockerfiles/*
 # subdirs with a matching name for the image
 aws s3 cp --recursive s3://openci-trustedfirmware-misra-${INFRA_ENV}/dockerfiles/ .
 find .
-aws ecr get-login-password --region us-east-1|docker login --username AWS --password-stdin $ECR
+aws ecr get-login-password --region eu-west-1|docker login --username AWS --password-stdin $ECR
 
 
 was_error=0
diff --git a/misra-docker-images/update.sh b/misra-docker-images/update.sh
index f185817..344f082 100755
--- a/misra-docker-images/update.sh
+++ b/misra-docker-images/update.sh
@@ -14,11 +14,11 @@
 fi
 
 aws configure list
-export ECR=987685672616.dkr.ecr.us-east-1.amazonaws.com
+export ECR=${PRIVATE_CONTAINER_REGISTRY}
 export REPO=misra
-aws ecr get-login-password --region us-east-1|docker login --username AWS --password-stdin $ECR
+aws ecr get-login-password --region eu-west-1|docker login --username AWS --password-stdin $ECR
 
-for image in $(aws ecr list-images --region us-east-1 --repository-name $REPO | \
+for image in $(aws ecr list-images --region eu-west-1 --repository-name $REPO | \
     grep imageTag | \
     awk '{print $2}' | \
     sed 's/"//g'); do