publish the link status in /net/ether?/status.

Reference: /n/sources/patch/applied/ether8169link
Date: Mon Feb 19 00:18:26 CET 2007
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/pc/ether8169.c	Mon Feb 19 00:17:25 2007
+++ /sys/src/9/pc/ether8169.c	Mon Feb 19 00:17:23 2007
@@ -796,8 +796,11 @@
 	 * Maybe the link changed - do we care very much?
 	 * Could stall transmits if no link, maybe?
 	 */
-	if(!((r = csr8r(ctlr, Phystatus)) & Linksts))
+	if(!((r = csr8r(ctlr, Phystatus)) & Linksts)){
+		edev->link = 0;
 		return;
+	}
+	edev->link = 1;
 
 	limit = 256*1024;
 	if(r & Speed10){