build-unit-test-docker: remove architecture checks

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

Tested:
- Confirmed ubuntu:latest works on ppc64le

Change-Id: Ic757d8317cb541e63fd51b29f5fdf4616d71797b
Signed-off-by: Andrew Geissler <geissonator@yahoo.com>
diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index 26c2964..a25f747 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -32,7 +32,7 @@
 # typing.Dict is used for type-hints.
 from typing import Any, Callable, Dict, Iterable, Optional  # noqa: F401
 
-from sh import docker, git, nproc, uname  # type: ignore
+from sh import docker, git, nproc  # type: ignore
 
 try:
     # Python before 3.8 doesn't have TypedDict, so reroute to standard 'dict'.
@@ -722,21 +722,6 @@
     gid = 0
     uid = 0
 
-# Determine the architecture for Docker.
-arch = uname("-m").strip()
-if arch == "ppc64le":
-    docker_base = "ppc64le/"
-elif arch == "x86_64":
-    docker_base = ""
-elif arch == "aarch64":
-    docker_base = "arm64v8/"
-else:
-    print(
-        f"Unsupported system architecture({arch}) found for docker image",
-        file=sys.stderr,
-    )
-    sys.exit(1)
-
 # Special flags if setting up a deb mirror.
 mirror = ""
 if "ubuntu" in distro and ubuntu_mirror:
@@ -780,7 +765,7 @@
 
 # Create base Dockerfile.
 dockerfile_base = f"""
-FROM {docker_base}{distro}
+FROM {distro}
 
 {mirror}