Revert "drm/amdgpu: Add pcie usage callback to nbio"

pcie usage is now handled by fw

This reverts commit 8d759dc6.

Signed-off-by: Asad Kamal <asad.kamal@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>