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.