build_helper_config: Add new dma350_ns config

The tf-m-extras repo has a new example for DMA350 NS tests.
Added the configuration for that so it can be used in the job-configs.

Change-Id: If5b75ef3698f2812377b60156632ef9e64bd2549
Signed-off-by: Bence Balogh <bence.balogh@arm.com>
2 files changed