Fix error introduced by patchusbserial-silabs (sorry), which opened the
input endpoint a second time as output, on some devices.

Reference: /n/sources/patch/applied/usbserial-epout
Date: Thu Feb 14 21:43:25 CET 2013
Signed-off-by: miller@hamnavoe.com

--- /sys/src/cmd/usb/serial/serial.c	Thu Feb 14 21:41:49 2013
+++ /sys/src/cmd/usb/serial/serial.c	Thu Feb 14 21:41:45 2013
@@ -718,7 +718,7 @@
 		if(ep->type == Ebulk){
 			if((ep->dir == Ein || ep->dir == Eboth) && epin == -1)
 				epin = ep->id;
-			if((ep->dir == Ein || ep->dir == Eboth) && epout == -1)
+			if((ep->dir == Eout || ep->dir == Eboth) && epout == -1)
 				epout = ep->id;
 		}
 	}