doc: board: ti: am62x_sk: Add labels to reuse memory map

Add labels around the A53 SPL DDR memory layout to be able to reuse the
memory map.

Signed-off-by: Nishanth Menon <nm@ti.com>
diff --git a/doc/board/ti/am62x_sk.rst b/doc/board/ti/am62x_sk.rst
index a482f52..16a4ab4 100644
--- a/doc/board/ti/am62x_sk.rst
+++ b/doc/board/ti/am62x_sk.rst
@@ -145,6 +145,8 @@
 A53 SPL DDR Memory Layout
 -------------------------
 
+.. am62x_evm_rst_include_start_ddr_mem_layout
+
 This provides an overview memory usage in A53 SPL stage.
 
 .. list-table::
@@ -198,6 +200,7 @@
    * - EMPTY
      - 0x80d00400
      - 0x81000000
+.. am62x_evm_rst_include_end_ddr_mem_layout
 
 Switch Setting for Boot Mode
 ----------------------------