feat(drtm): update return code if secondary PE is not off

DRTM 1.0 specifies that if any secondary PEs are not off
during a dynamic launch the return code must be
SECONDARY_PE_NOT_OFF.

Signed-off-by: Stuart Yoder <stuart.yoder@arm.com>
Change-Id: Idcb1f3c60daa63a5bc994bdeacca8aab7066f628
1 file changed