LU-18461 lod: let's remove home coded lu_buf code.

LU-18461 lod: let's remove home coded lu_buf code.

lti_ea_store and lti_ea_store_size is same is lu_buf,
lets drop code duplication.

Test-Parameters: trivial
Signed-off-by: Alexey Lyashkov <alexey.lyashkov@hpe.com>
Change-Id: I3a61382e53a848c94654bc4c55b7ac0c97758dbb
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/57188
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Timothy Day <timday@amazon.com>