tty: serial: 8250: Fix wording in runtime-PM comments

Frans reworded the two comments with better English for better
understanding. His review hit the mailing list after the patch got
applied so here is an incremental update.
Reported-by: NFrans Klaver <frans.klaver@xsens.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_core.c

@@ -557,7 +557,7 @@ static void serial8250_rpm_put(struct uart_8250_port *p)
 }
 
 /*
- * This two wrapper ensure, that enable_runtime_pm_tx() can be called more than
+ * These two wrappers ensure that enable_runtime_pm_tx() can be called more than
  * once and disable_runtime_pm_tx() will still disable RPM because the fifo is
  * empty and the HW can idle again.
  */
@@ -1535,7 +1535,7 @@ void serial8250_tx_chars(struct uart_8250_port *up)
 	DEBUG_INTR("THRE...");
 
 	/*
-	 * With RPM enabled, we have to wait once the FIFO is empty before the
+	 * With RPM enabled, we have to wait until the FIFO is empty before the
 	 * HW can go idle. So we get here once again with empty FIFO and disable
 	 * the interrupt and RPM in __stop_tx()
 	 */