bcm47xx: make it possible to build bcm47xx without ssb.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/arch/mips/bcm47xx/Makefile b/arch/mips/bcm47xx/Makefile
index 7465e8a..4add173 100644
--- a/arch/mips/bcm47xx/Makefile
+++ b/arch/mips/bcm47xx/Makefile
@@ -3,4 +3,5 @@
 # under Linux.
 #
 
-obj-y := gpio.o irq.o nvram.o prom.o serial.o setup.o time.o wgt634u.o
+obj-y 				+= gpio.o irq.o nvram.o prom.o serial.o setup.o time.o
+obj-$(CONFIG_BCM47XX_SSB)	+= wgt634u.o