serial: uniphier: fix typo in comment

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/drivers/serial/serial_uniphier.c b/drivers/serial/serial_uniphier.c
index 4004cb8..a098028 100644
--- a/drivers/serial/serial_uniphier.c
+++ b/drivers/serial/serial_uniphier.c
@@ -137,7 +137,7 @@
 
 	priv->uartclk = clk_data->clk_rate;
 
-	/* flush the trasmitter empty before changing hw setting */
+	/* flush the trasmitter before changing hw setting */
 	while (!(readl(priv->membase + UNIPHIER_UART_LSR) & UART_LSR_TEMT))
 		;