LU-8066 sysfs: migrate checksum_type to sys/fs tree

LU-8066 sysfs: migrate checksum_type to sys/fs tree

The checksum_type file is simple so the logical place is sys/fs
which is accessible to everyone. This more complex file is
one of thew few allowed in the general sysfs tree.

Change-Id: I6ce89416ef64058f911e18a3f743944f0a6a8f4e
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56667
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Timothy Day <timday@amazon.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>