Build: Fix scatter file target depedencies

The scatter file target collects scatter file for linking.
The target include region definitions and flash layout to preprocess the
scatter file.

The scatter file target shall link an INTERFACE library to get memory
layout information.
However, scatter file target links STATIC library platform_ns now. If
platform_ns include INTERFACE/PUBLIC source files or libraries, linker
will take those INTERFACE/PUBLIC stuff as linker script by mistake and
break the linking.

Fix the dependencies by creating a dedicated INTERFACE target:
platform_regions_defs to provide memory layout information and other NS
configurations.

Change-Id: I62f6dac0d8a64a099aa09fdd1bdb80f7f8afb2fc
Signed-off-by: David Hu <david.hu@arm.com>
4 files changed