bcma: allow disabling (not building) PCI driver

It isn't required for bcma bus on SoCs, so provide some empty functions
and allow disabling it.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --cc drivers/bcma/Kconfig
Simple merge

diff --cc drivers/bcma/bcma_private.h
Simple merge

diff --cc include/linux/bcma/bcma_driver_pci.h
Simple merge