use the recommended 1/2 second keyboard repeat; this helps
when timers are working against us

Reference: /n/atom/patch/applied2013/usbrpt
Date: Tue Jun 18 21:38:41 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/usb/kb/kb.c	Tue Jun 18 21:38:25 2013
+++ /sys/src/cmd/usb/kb/kb.c	Tue Jun 18 21:38:25 2013
@@ -456,7 +456,7 @@
 		goto Abort;
 	esc1 = l >> 8;
 	sc = l;
-	t = 160;
+	t = 500;
 	for(;;){
 		for(i = 0; i < t; i += 5){
 			if(l = nbrecvul(repeatc))