bcma: Prevent build of PCI host features in module

Attempting to build bcma.ko with BCMA_DRIVER_PCI_HOSTMODE=y results in
a build error due to use of symbols not exported from vmlinux:

ERROR: "pcibios_enable_device" [drivers/bcma/bcma.ko] undefined!
ERROR: "register_pci_controller" [drivers/bcma/bcma.ko] undefined!
make[1]: *** [scripts/Makefile.modpost:92: __modpost] Error 1

To prevent this, don't allow the host mode feature to be built if
CONFIG_BCMA=m
Signed-off-by: Matt Redfearn <matt.redfearn@mips.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/bcma/Kconfig

@@ -55,7 +55,7 @@ config BCMA_DRIVER_PCI
 
 config BCMA_DRIVER_PCI_HOSTMODE
 	bool "Driver for PCI core working in hostmode"
-	depends on MIPS && BCMA_DRIVER_PCI && PCI_DRIVERS_LEGACY
+	depends on MIPS && BCMA_DRIVER_PCI && PCI_DRIVERS_LEGACY && BCMA = y
 	help
 	  PCI core hostmode operation (external PCI bus).