dm: video: Refactor lcd_simplefb to prepare for driver model

Adjust this function so that we can convert it to support CONFIG_DM_VIDEO
without a lot of code duplication.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Anatolij Gustschin <agust@denx.de>
diff --git a/common/lcd_simplefb.c b/common/lcd_simplefb.c
index 2ba00f6..e479b49 100644
--- a/common/lcd_simplefb.c
+++ b/common/lcd_simplefb.c
@@ -16,17 +16,28 @@
 
 static int lcd_dt_simplefb_configure_node(void *blob, int off)
 {
-	int vl_col = lcd_get_pixel_width();
-	int vl_row = lcd_get_pixel_height();
-#if LCD_BPP == LCD_COLOR16
-	return fdt_setup_simplefb_node(blob, off, gd->fb_base, vl_col, vl_row,
-				       vl_col * 2, "r5g6b5");
-#elif LCD_BPP == LCD_COLOR32
-	return fdt_setup_simplefb_node(blob, off, gd->fb_base, vl_col, vl_row,
-				       vl_col * 4, "a8r8g8b8");
-#else
-	return -1;
-#endif
+	int xsize, ysize;
+	int bpix; /* log2 of bits per pixel */
+	const char *name;
+	ulong fb_base;
+
+	xsize = lcd_get_pixel_width();
+	ysize = lcd_get_pixel_height();
+	bpix = LCD_BPP;
+	fb_base = gd->fb_base;
+	switch (bpix) {
+	case 4: /* VIDEO_BPP16 */
+		name = "r5g6b5";
+		break;
+	case 5: /* VIDEO_BPP32 */
+		name = "a8r8g8b8";
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return fdt_setup_simplefb_node(blob, off, fb_base, xsize, ysize,
+				       xsize * (1 << bpix) / 8, name);
 }
 
 int lcd_dt_simplefb_add_node(void *blob)