drm/amd/amdgpu: fix PCIe dpm feature issue (v3)

use pcie_bandwidth_available to get real link state
to update pcie table.

v2: fix incorrect initialized return value
v3: expand the fetching method about the link width to all asics.

Signed-off-by: Chengming Gui <Jack.Gui@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>