docker: remove architecture checks

Docker containers now handle this under the covers when you pull a
container.

Change-Id: If0062f68c53ca79735dd841ae06236c34911e081
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/build-rootfs-size-docker.sh b/build-rootfs-size-docker.sh
index 325d8c8..4acd278 100755
--- a/build-rootfs-size-docker.sh
+++ b/build-rootfs-size-docker.sh
@@ -20,23 +20,6 @@
 DOCKER_IMG_NAME=${DOCKER_IMG_NAME:-"openbmc/ubuntu-rootfs-size"}
 DISTRO=${DISTRO:-"ubuntu:bionic"}
 
-# Determine the architecture
-ARCH=$(uname -m)
-case ${ARCH} in
-    "ppc64le")
-        DOCKER_BASE="ppc64le/"
-        ;;
-    "x86_64")
-        DOCKER_BASE=""
-        ;;
-    "aarch64")
-        DOCKER_BASE="arm64v8/"
-        ;;
-    *)
-        echo "Unsupported system architecture(${ARCH}) found for docker image"
-        exit 1
-esac
-
 PROXY=""
 
 MIRROR=""
@@ -57,7 +40,7 @@
     fi
 
     Dockerfile=$(cat << EOF
-FROM ${DOCKER_BASE}${DISTRO}
+FROM ${DISTRO}
 
 ${PROXY}
 ${MIRROR}