LU-16199 ldiskfs: make ubuntu kernel version detection better

LU-16199 ldiskfs: make ubuntu kernel version detection better

Ubuntu kernel version detection is not working correctly with
official versioning scheme.  There are also a couple of errors in the
AS_VERSION_COMPARE sequences causing problems for 5.4.0 and later.

Signed-off-by: Ake Sandgren <ake.sandgren@hpc2n.umu.se>
Change-Id: Ie6e51de95ae1513b15ee0c2baa8c421f3cb954f5
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/48717
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>