driver core: Remove unused parameter for virtual_device_parent()

Function struct kobject *virtual_device_parent(struct device *dev)
does not use its parameter @dev, and the kobject returned also has
nothing deal with specific device, so remove the unused parameter.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Link: https://lore.kernel.org/r/20240725-virtual_kobj_fix-v1-1-36335cae4544@quicinc.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>