drm/amdgpu: fix pci device refcount leak

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: fix pci device refcount leak As comment of pci_get_domain_bus_and_slot() says, it returns a pci device with refcount increment, when finish using it, the caller must decrement the reference count by calling pci_dev_put(). So before returning from amdgpu_device_resume|suspend_display_audio(), pci_dev_put() is called to avoid refcount leak.