ftdi: incorrectly using output register for direction

fix a simple copy/paste bug.

Change-Id: I5caaa4d16d30f26a453bd6a00c95261fd6e716c5
Signed-off-by: Spencer Oliver <spen@spen-soft.co.uk>
Reviewed-on: http://openocd.zylin.com/873
Tested-by: jenkins

src/jtag/drivers/ftdi.c

@@ -175,7 +175,7 @@ static int ftdi_set_signal(const struct signal *s, char value)
 
 	output = data ? output | s->data_mask : output & ~s->data_mask;
 	if (s->oe_mask == s->data_mask)
-		direction = oe ? output | s->oe_mask : output & ~s->oe_mask;
+		direction = oe ? direction | s->oe_mask : direction & ~s->oe_mask;
 	else
 		output = oe ? output | s->oe_mask : output & ~s->oe_mask;