net: doc: merge /proc/sys/net/core/* documents into one place

All parameter descriptions in /proc/sys/net/core/* now is separated
two places. So, merge them into Documentation/sysctl/net.txt.

Signed-off-by: Shan Wei <davidshan@tencent.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/Documentation/sysctl/net.txt b/Documentation/sysctl/net.txt
index 3201a70..98335b7 100644
--- a/Documentation/sysctl/net.txt
+++ b/Documentation/sysctl/net.txt
@@ -43,6 +43,13 @@
 	1 - enable the JIT
 	2 - enable the JIT and ask the compiler to emit traces on kernel log.
 
+dev_weight
+--------------
+
+The maximum number of packets that kernel can handle on a NAPI interrupt,
+it's a Per-CPU variable.
+Default: 64
+
 rmem_default
 ------------