PCI/VGA: Remove empty vga_arb_device_card_gone()

vga_arb_device_card_gone() has always been empty.  Remove it.

Link: https://lore.kernel.org/r/20220224224753.297579-9-helgaas@kernel.org


Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>