video: cfb_console: add weak default video_set_lut()

Do not enforce drivers to provide empty video_set_lut()
if they do not implement indexed color (8 bpp) frame
buffer support. Add default function to the cfb_console
driver and remove empty video_set_lut() functions.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/video/cfb_console.c b/drivers/video/cfb_console.c
index d1f47c9..96d52fb 100644
--- a/drivers/video/cfb_console.c
+++ b/drivers/video/cfb_console.c
@@ -749,6 +749,18 @@
 
 /*****************************************************************************/
 
+/*
+ * Do not enforce drivers (or board code) to provide empty
+ * video_set_lut() if they do not support 8 bpp format.
+ * Implement weak default function instead.
+ */
+void __video_set_lut (unsigned int index, unsigned char r,
+		      unsigned char g, unsigned char b)
+{
+}
+void video_set_lut (unsigned int, unsigned char, unsigned char, unsigned char)
+			__attribute__((weak, alias("__video_set_lut")));
+
 #if defined(CONFIG_CMD_BMP) || defined(CONFIG_SPLASH_SCREEN)
 
 #define FILL_8BIT_332RGB(r,g,b)	{			\
diff --git a/drivers/video/sm501.c b/drivers/video/sm501.c
index 283d2d9..8c96316 100644
--- a/drivers/video/sm501.c
+++ b/drivers/video/sm501.c
@@ -131,16 +131,3 @@
 
 	return (&sm501);
 }
-
-/*-----------------------------------------------------------------------------
- * video_set_lut --
- *-----------------------------------------------------------------------------
- */
-void video_set_lut (
-	unsigned int index,           /* color number */
-	unsigned char r,              /* red */
-	unsigned char g,              /* green */
-	unsigned char b               /* blue */
-	)
-{
-}