Core: Only allow PRoT services to make reset request

Only allow reset requests that are coming from a PSA Root of Trust
secure service.

Also make test service, that is making an SPM requests to be PRoT

Change-Id: Id89a619db4e59f7460600351081a231dab3a366e
Signed-off-by: Mate Toth-Pal <mate.toth-pal@arm.com>