GitLab

- Implement INBOX0 messaging for HW lock
Signed-off-by: Anthony Koo <Anthony.Koo@amd.com>
Acked-by: Stylon Wang <stylon.wang@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>