LU-9019 osd-ldiskfs: migrate to 64 bit time

LU-9019 osd-ldiskfs: migrate to 64 bit time

Replace cfs_time_current_sec() to avoid the overflow issues in
2038 with ktime_get_real_seconds(). Besides changing struct
scrub_file sf_time_* fields to time64_t for usage with
ktime_get_real_seconds() the other fields can also be moved to
time64_t as well since we don't need precision better than one
second for the scrubbing code. The dr_* time fields in struct
osd_iobuf are jiffies which does get reporting with the histograms.
This was with the thinking that jiffies equal milliseconds which
is not always the case. Since we need better than one second
resolution move dr_* time fields to ktime. This way the value
passed to lprocfs_oh_tally_log() will always be in milliseconds.

Change-Id: Ibce7f7d9f972c8d3188271950f68dcda7663676f
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/29857
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>