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.

Fixes: 3f12acc8 ("drm/amdgpu: put the audio codec into suspend state before gpu reset V3")
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>