Add json merger tool

Add a simple script to merge two json files. It's necessary for creating
the sp_layout.json required by TF-A for using FIP SPs.

Signed-off-by: Balint Dobszay <balint.dobszay@arm.com>
Change-Id: I944770d263921efcbb12217db3df5170c59f8fec
2 files changed