doc: board: fix README.b4860qds

Two sibling headings can never be the same.

Fix the heading levels.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/doc/board/freescale/b4860qds.rst b/doc/board/freescale/b4860qds.rst
index 37d7d08..de14d85 100644
--- a/doc/board/freescale/b4860qds.rst
+++ b/doc/board/freescale/b4860qds.rst
@@ -134,7 +134,7 @@
 -------------------------
 
 Switch Settings
----------------
+^^^^^^^^^^^^^^^
 
 .. code-block:: none
 
@@ -167,7 +167,7 @@
 -------------------------
 
 Switch Settings
----------------
+^^^^^^^^^^^^^^^
 
 .. code-block:: none