LU-9633 llite: Add kernel doc style for lustre/llite/*.c (Part 6)

LU-9633 llite: Add kernel doc style for lustre/llite/*.c (Part 6)

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:
./kernel-doc -v -none lustre/llite/llite_mmap.c lustre/llite/llite_nfs.c
lustre/llite/llite_mmap.c:72: info: Scanning doc for function ll_fault_io_init
lustre/llite/llite_mmap.c:266: info: Scanning doc for function ll_fault0
lustre/llite/llite_mmap.c:536: info: Scanning doc for function ll_vm_open
lustre/llite/llite_mmap.c:560: info: Scanning doc for function ll_vm_close
lustre/llite/llite_nfs.c:234: info: Scanning doc for function ll_encode_fh

Test-Parameters: trivial
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: I31cc93b570db31550aa3bdc919dbd8ce82ce47a4
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/58278
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Petros Koutoupis <petros.koutoupis@hpe.com>
Reviewed-by: Anjus George <georgea@ornl.gov>
Reviewed-by: Oleg Drokin <green@whamcloud.com>