doc: boards: amlogic: Add documentation on pre-generated FIP files

It add documentation on licencing & provides links to the amlogic-boot-fip
pre-built files collections.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
diff --git a/doc/board/amlogic/odroid-n2.rst b/doc/board/amlogic/odroid-n2.rst
index fe63113..7aad36e 100644
--- a/doc/board/amlogic/odroid-n2.rst
+++ b/doc/board/amlogic/odroid-n2.rst
@@ -29,6 +29,8 @@
 Image creation
 --------------
 
+For simplified usage, pleaser refer to :doc:`pre-generated-fip` with codename `odroid-n2` or `odroid-n2-plus`
+
 Amlogic doesn't provide sources for the firmware and for tools needed
 to create the bootloader image, so it is necessary to obtain them from
 the git tree published by the board vendor: