drm/amdgpu: add gfx11 hw debug mode enable and disable calls

Implement the per-device calls to enable or disable HW debug mode
for GFX11.

Signed-off-by: Jonathan Kim <jonathan.kim@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>