LU-6142 osd-ldiskfs: SPDX for ldiskfs OSD

LU-6142 osd-ldiskfs: SPDX for ldiskfs OSD

Convert from verbose license text to SPDX.

Test-Parameters: trivial
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: Ie9a298fcf9999af1edfbf1acb58c23d7c83fbb7c
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/55613
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>