PCI: Add pci_clear_master() stub for non-CONFIG_PCI

Add a pci_clear_master() stub when CONFIG_PCI is not set so drivers that
support both PCI and platform devices don't need #ifdefs or extra Kconfig
symbols for the PCI parts.

[bhelgaas: commit log]
Fixes: 6a479079 ("PCI: Add pci_clear_master() as opposite of pci_set_master()")
Link: https://lore.kernel.org/r/20230531102744.2354313-1-suijingfeng@loongson.cn


Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>