Documentation/sysctl/net.txt: fix (attribute removal).

This patch removes mentioning the sysfsf net_device weight attribute
(class/net/<device>/weight)
in Documentation/sysctl/net.txt, since the net sysfs weight attribute
was removed by the following patch:

[NET]: Make NAPI polling independent of struct net_device objects
 bea3348e

Signed-off-by: Rami Rosen <ramirose@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/sysctl/net.txt

@@ -93,8 +93,7 @@ netdev_budget
 
 Maximum number of packets taken from all interfaces in one polling cycle (NAPI
 poll). In one polling cycle interfaces which are registered to polling are
-probed in a round-robin manner. The limit of packets in one such probe can be
-set per-device via sysfs class/net/<device>/weight .
+probed in a round-robin manner.
 
 netdev_max_backlog
 ------------------