LU-18080 ldiskfs: support NO_CHECKS for Ubunutu and SuSE15

LU-18080 ldiskfs: support NO_CHECKS for Ubunutu and SuSE15

Backport the special NO_CHECKS flag for Ubuntu and SuSE15 that
was missing. Without it you get the build error:

osd_scrub.c:656:42: error: ‘LDISKFS_IGET_NO_CHECKS’ undeclared ...

Also add ext4-filename-encode.patch for Ubuntu 20.04.

Test-Parameters: trivial
Signed-off-by: James Simmons <jsimmons@infradead.org>
Change-Id: I1022b0f4a1b5ee818596ca3aece3f886a5721d25
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55985
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>