staging: lustre: discard CFS_TICK

This undocumented macro seems to represent "a small amount of time".
Sometimes it is used as-is, some times it is multiplied by 5 for no
obvious reason.
It does not appear that there is any connection between the different
places it is used - they all just want a short period for different
purposes and of different durarions.

So discard CFS_TICK and lets each use-site just use whatever number
of jiffies seems appropriate in that case.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>