LU-6142 selftest: SPDX for lnet/selftest/

LU-6142 selftest: SPDX for lnet/selftest/

Convert from verbose license text to SDPX.

Test-Parameters: trivial
Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: I131a74e146c02e601c2474f648550b1bedf37a28
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/54171
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Oleg Drokin <green@whamcloud.com>