LU-8066 llite: move /proc/fs/lustre/llite/checksum_pages to sysfs

LU-8066 llite: move /proc/fs/lustre/llite/checksum_pages to sysfs

Move checksum_pages file from /proc/fs/lustre/llite/*
to /sys/fs/lustre/llite/*/

This is a modified version of

Linux-commit: 40cc864a9fcd48d7f3a67421a8e578e8d4cbe308

due to the large amount of changes to the OpenSFS/Intel branch.

Change-Id: Ice48c69503680ac995b60844a8d0d7ae2bddd102
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/32502
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Sonia Sharma <sharmaso@whamcloud.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>