video: Fix unchnaged typo

Fix this typo in the header file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/include/video.h b/include/video.h
index 43f2e2c..3f67a93 100644
--- a/include/video.h
+++ b/include/video.h
@@ -248,7 +248,7 @@
  *		  that direction
  *		- if a coordinate is -ve then it will be offset to the
  *		  left/top of the centre by that many pixels
- *		- if a coordinate is positive it will be used unchnaged.
+ *		- if a coordinate is positive it will be used unchanged.
  * Return: 0 if OK, -ve on error
  */
 int video_bmp_display(struct udevice *dev, ulong bmp_image, int x, int y,