LU-9633 llite: Add kernel doc style for lustre/llite/*.c (Part 1)

LU-9633 llite: Add kernel doc style for lustre/llite/*.c (Part 1)

This patch converts existing functional comments
to kernel doc style comments and removes '/**' for
comments which is not meant to be a kernel-doc comment

Tested with:
<kernel src path>/scrips/kernel-doc -v -none <file>

Pass criteria: No errors/warnings reported

Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I90643c70bc5ecfbcc90504da1a5b3b3ea67e3381
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/57725
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>