doc: migration guide: display: Mention rgb565/bgr565 fix

Mention that the RGB565 and BGR565 interchange issue has been fixed
in the display sample.

Signed-off-by: Phi Bang Nguyen <[email protected]>

Author: ngphibang

doc/releases/migration-guide-4.3.rst

@@ -68,6 +68,13 @@ Networking
 
 .. zephyr-keep-sorted-stop
 
+Display
+*******
+
+* The RGB565 and BGR565 pixel formats were used interchangeably in the display sample.
+  This has now been fixed. Boards and applications that were tested or developed based on the
+  previous sample may be affected by this change (see :github:`79996` for more information).
+
 Other subsystems
 ****************