[NET_SCHED]: Show timer resolution instead of clock resolution in /proc/net/psched

The fourth parameter of /proc/net/psched is supposed to show the timer
resultion and is used by HTB userspace to calculate the necessary
burst rate. Currently we show the clock resolution, which results in a
too low burst rate when the two differ.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>