ssb: add Kconfig entry for compiling SoC related code

This allows saving a little of space when not using ssb on Broadcom SoC.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
diff --git a/arch/mips/bcm47xx/Kconfig b/arch/mips/bcm47xx/Kconfig
index 51ed599..e970fd9 100644
--- a/arch/mips/bcm47xx/Kconfig
+++ b/arch/mips/bcm47xx/Kconfig
@@ -4,6 +4,7 @@
 	bool "SSB Support for Broadcom BCM47XX"
 	select SYS_HAS_CPU_BMIPS32_3300
 	select SSB
+	select SSB_HOST_SOC
 	select SSB_DRIVER_MIPS
 	select SSB_DRIVER_EXTIF
 	select SSB_EMBEDDED