Revert "lakitu: switch kdump kernel to Linux 5.10"

This reverts commit 307a9ea6c6b6a04c2efd760c73994ff98e0f5263.

Reason for revert: Broke some build targets, see b/186477404

Change-Id: I85b7409e943287f70fb255cd5413c47dff0a1612
Reviewed-on: https://cos-review.googlesource.com/c/cos/overlays/board-overlays/+/15990
Reviewed-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Tested-by: Robert Kolchmeyer <rkolchmeyer@google.com>
6 files changed