contrib: fix minor typos

While there, replace s/return(0)/return 0/ that causes checkpatch
to fail.

Change-Id: I5ad54cffca629475563c471114a9f77301a9e4f8
Signed-off-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-on: http://openocd.zylin.com/5768
Tested-by: jenkins

contrib/itmdump.c

@@ -325,7 +325,7 @@ static void show_timestamp(FILE *f, int c)
 		delayed = true;
 		break;
 	case 0xf:
-		label = ", packet and timetamp delayed";
+		label = ", packet and timestamp delayed";
 		delayed = true;
 		break;
 	}