lib: addr_map: Move address_map[] type to the header file

lib: addr_map: Move address_map[] type to the header file

At present address_map[] is static and its type is unknown to external
modules. In preparation to create a command to list its contents, this
patch moves its type definition and declaration to the header file.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>