configs/rde1edge: adapt to changes in edk2-platforms

There are changes in edk2-platforms which requires each of the platform
to have its own platform description file. Adapt to these changes
in edk2-platforms repo.

Change-Id: I01b94088947e93381975dd9c4d2e9ebdcb277357
Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>