tier-1: drop unused kdump-aarch64-aws-workaround.yaml

At least in this repo's history, this file doesn't appear to have ever
been used.

tier-1/kdump-aarch64-aws-workaround.yaml

@@ -1,12 +0,0 @@
-# This file includes a fixup for kdump on aarch64 AWS instances.
-# The issue seems specific to aarch64 AWS instances, but we'll go
-# ahead and apply it across the board for aarch64, since that's
-# the easiest thing to do. Hopefully the upstream issue will get
-# resolved soon.
-postprocess:
-  - |
-    #!/usr/bin/env bash
-    # Remove irqpoll from the list of KDUMP_COMMANDLINE_APPEND. This
-    # causes issues on aarch64 AWS instances.
-    # https://github.com/coreos/fedora-coreos-tracker/issues/1187
-    sed -i -e 's/irqpoll //' /etc/sysconfig/kdump