serial: Call flush() before changing baudrate

Changing baudrate is a sensitive operation. To ensure that U-Boot messages
printed before changing baudrate are not lost, call new U-Boot console
flush() function.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/load.c b/cmd/load.c
index e44ae0d..5c4f347 100644
--- a/cmd/load.c
+++ b/cmd/load.c
@@ -83,6 +83,7 @@
 		printf("## Switch baudrate to %d bps and press ENTER ...\n",
 			load_baudrate);
 		udelay(50000);
+		flush();
 		gd->baudrate = load_baudrate;
 		serial_setbrg();
 		udelay(50000);
@@ -126,6 +127,7 @@
 		printf("## Switch baudrate to %d bps and press ESC ...\n",
 			current_baudrate);
 		udelay(50000);
+		flush();
 		gd->baudrate = current_baudrate;
 		serial_setbrg();
 		udelay(50000);
@@ -317,6 +319,7 @@
 		printf("## Switch baudrate to %d bps and press ESC ...\n",
 			(int)current_baudrate);
 		udelay(50000);
+		flush();
 		gd->baudrate = current_baudrate;
 		serial_setbrg();
 		udelay(50000);
@@ -471,6 +474,7 @@
 		printf("## Switch baudrate to %d bps and press ENTER ...\n",
 			load_baudrate);
 		udelay(50000);
+		flush();
 		gd->baudrate = load_baudrate;
 		serial_setbrg();
 		udelay(50000);
@@ -533,6 +537,7 @@
 		printf("## Switch baudrate to %d bps and press ESC ...\n",
 			current_baudrate);
 		udelay(50000);
+		flush();
 		gd->baudrate = current_baudrate;
 		serial_setbrg();
 		udelay(50000);
diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
index 53df10e..da3e1eb 100644
--- a/drivers/serial/serial-uclass.c
+++ b/drivers/serial/serial-uclass.c
@@ -476,6 +476,7 @@
 			printf("## Switch baudrate to %d bps and press ENTER ...\n",
 			       baudrate);
 			udelay(50000);
+			flush();
 		}
 
 		gd->baudrate = baudrate;