tcp: Fix comments for Nagle algorithm

TCP_NODELAY is weaker than TCP_CORK, when TCP_CORK was set, small
segments will always pass Nagle test regardless of TCP_NODELAY option.

Signed-off-by: Feng King <kinwin2008@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 980b98f..63170e2 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1382,7 +1382,7 @@
 /* Return 0, if packet can be sent now without violation Nagle's rules:
  * 1. It is full sized.
  * 2. Or it contains FIN. (already checked by caller)
- * 3. Or TCP_NODELAY was set.
+ * 3. Or TCP_CORK is not set, and TCP_NODELAY is set.
  * 4. Or TCP_CORK is not set, and all sent packets are ACKed.
  *    With Minshall's modification: all sent small packets are ACKed.
  */