LU-8066 mdd: migrate from proc to sysfs

LU-8066 mdd: migrate from proc to sysfs

Move the ofd module from using proc for most single value files
to sysfs. The more complex proc entries are moved to debugfs.

Lustre-change: https://review.whamcloud.com/33632
Lustre-commit: e783bbffe35b2b8ebebde5bc70abf288d07df5a3

Change-Id: I01eebf1c58f1a13c2f5e8c599a1363c80468b0bd
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Signed-off-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/37005
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>