drivers/net: normalize TX_TIMEOUT

Some network drivers use old TX_TIMEOUT definitions, assuming HZ=100 of
old kernels.

Convert these definitions to include HZ, since HZ can be 1000 these
days.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/82596.c b/drivers/net/82596.c
index e2c9c5b..be1f197 100644
--- a/drivers/net/82596.c
+++ b/drivers/net/82596.c
@@ -191,7 +191,7 @@
 #define	 RX_SUSPEND	0x0030
 #define	 RX_ABORT	0x0040
 
-#define TX_TIMEOUT	5
+#define TX_TIMEOUT	(HZ/20)
 
 
 struct i596_reg {