LU-8066 obdclass: move lustre sysctl to sysfs

LU-8066 obdclass: move lustre sysctl to sysfs

Backport from upstream the changes to port lustre
systctl to sysfs. Needed to re-export the function
lprocfs_read_frac_helper for later work. The
following patches were backported:

Fix class_procfs_init error return value. Dan Carpenter noticed
that procfs conversion patches introduced a bug where should
kobject_create_and_add, an error is not returned from
class_procfs_init.

Linux-commit: 3c4872f94359ed38a1392c0a9238c48a9aee6f8f

Move sysctl timeout to sysfs. This is the first step of
moving lustre sysctls from /proc/sys/lustre to /sys/fs/lustre

Linux-commit: e2424a1265f2772b66f068c205256e2aef5f74a0

Move max_dirty_mb from sysctl to sysfs. max_dirty_mb is
now a parameter in /sys/fs/lustre.

Linux-commit: df476a4d5de09d9324b108fc9c5ff2c00a0850d0

Move debug controls to sysfs. debug_peer_on_timeout,
dump_on_timeout and dump_on_eviction controls from
/proc/sys/lustre to /sys/fs/lustre

Linux-commit: 9e7fa14935901bcd09576b2866d5dd15f69caf83

Move AT controls from sysctl to sysfs. Adaptive Timeouts
controls are being moved from /proc/sys/lustre to
/sys/fs/lustre

Linux-commit: bcef118e7ed67e28edcaab9be9ca11412176c540

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Change-Id: Id1b00bebf9ecca5284e9c71f4c0f91e56cbf391b
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/23428
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>