video: Drop unnecessary #ifdef around vid_console_color()

All of the functions in this file only apply if DM_VIDEO is enabled. Drop
the #ifdef as it just clutters things up. Add the needed forward
declaration.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Anatolij Gustschin <agust@denx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/include/video_console.h b/include/video_console.h
index 0936cea..d3bc063 100644
--- a/include/video_console.h
+++ b/include/video_console.h
@@ -8,6 +8,8 @@
 
 #include <video.h>
 
+struct video_priv;
+
 #define VID_FRAC_DIV	256
 
 #define VID_TO_PIXEL(x)	((x) / VID_FRAC_DIV)
@@ -241,8 +243,6 @@
 void vidconsole_position_cursor(struct udevice *dev, unsigned col,
 				unsigned row);
 
-#ifdef CONFIG_DM_VIDEO
-
 /**
  * vid_console_color() - convert a color code to a pixel's internal
  * representation
@@ -257,5 +257,3 @@
 u32 vid_console_color(struct video_priv *priv, unsigned int idx);
 
 #endif
-
-#endif