PCI: Remove obsolete pci_cleanup_rom() declaration

Commit d9c8bea1 ("PCI: Remove unused IORESOURCE_ROM_COPY and
IORESOURCE_ROM_BIOS_COPY") removed pci_cleanup_rom(), but retained
its declaration in pci.h.

Remove it.

Link: https://lore.kernel.org/r/fc30de5276e21d5a3ebcb7e58a8b43e399f7e6e6.1698668982.git.lukas@wunner.de


Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>