cmake: Add functionality for external products directory
Add functionality to allow the user to build products that are not in the SCP-firmware directory tree. The user is able to add an optional parameter in the make command called PRODUCT_PATH
. This specifies where the external products directory is. Then PRODUCT
will search in this folder instead. If a product is to be added that will be built outside of the SCP-firmware directory tree, then they should follow the instructions in the documentation in this MR.
Signed-off-by: James Chesterman James.Chesterman@arm.com