net: e1000: typo using wrong argument to sizeof

Typo from 4b29bdb0ed08412d225a8be94f61fc6c37a59dd5

Signed-off-by: Matthew McClintock <msm@freescale.com>

drivers/net/e1000.c

@@ -5189,7 +5189,7 @@ e1000_initialize(bd_t * bis)
 			return 0;
 		}
 
-		memset(nic, 0, sizeof(*dev));
+		memset(nic, 0, sizeof(*nic));
 		memset(hw, 0, sizeof(*hw));
 
 		hw->pdev = devno;