fbcon: flush the display after the background updating

Needed if the display requires the data to be manually redrawn after
screen updates.

Change-Id: I4b4d42849f3712d2c0cec1eaa89e09aa3dd3ccb5
diff --git a/dev/fbcon/fbcon.c b/dev/fbcon/fbcon.c
index f2296a4..5bce3c2 100644
--- a/dev/fbcon/fbcon.c
+++ b/dev/fbcon/fbcon.c
@@ -109,6 +109,8 @@
 					[FBCON_SELECT_MSG_BG_COLOR] = {RGB888_WHITE, RGB888_BLUE}};
 
 
+static void fbcon_flush(void);
+
 static void fbcon_drawglyph(char *pixels, uint32_t paint, unsigned stride,
 			    unsigned bpp, unsigned *glyph, unsigned scale_factor)
 {
@@ -211,6 +213,7 @@
 			pixels += config->bpp / 8;
 		}
 	}
+	fbcon_flush();
 }
 
 static void fbcon_flush(void)