LU-8541 ldlm: don't use jiffies as sysfs parameter

LU-8541 ldlm: don't use jiffies as sysfs parameter

The ldlm sysfs file handles lru_max_age in jiffies which is wrong
since jiffies are not consistent across machine since HZ is
configurable at compile time. Talking to most users they thought
lru_max_age was in seconds which is incorrect. The best way to
fix this is to move lru_max_age to millisecs since most systems
lustre deals with sets HZ to 1000. To make it clear it is in
milliseconds print out lru_max_age with "ms". Since users tend
to think in seconds allow passing in seconds besides milliseconds
and internally converting them to nanaseconds. Since we have to
support milliseconds move to ktime_t since we can't use time64_t.
Unfortunately, this makes a relatively large patch, but I could
not find a way to split it up some more without breaking atomicity
of the change.

Change-Id: I0b1814fd9d903767f62fe141d2c95845b75fb95a
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/28370
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>