Partially test bl1_fwu

Add tests for bl1_fwu_add_loaded_id and bl1_fwu_remove_loaded_id.
c-picker was used for isolating these two functions from the rest of
the code.

Change-Id: I39259c6b845547e112385806e334733c986d56d3
Signed-off-by: Imre Kis <imre.kis@arm.com>
4 files changed