[POWERPC] scc_sio: Fix link failure

scc_sio.o should only be built if the txx9 serial driver is actually
built into the kernel.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

--
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/celleb/Makefile b/arch/powerpc/platforms/celleb/Makefile
index f4f8252..5240046 100644
--- a/arch/powerpc/platforms/celleb/Makefile
+++ b/arch/powerpc/platforms/celleb/Makefile
@@ -4,5 +4,5 @@
 
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_PPC_UDBG_BEAT)	+= udbg_beat.o
-obj-$(CONFIG_HAS_TXX9_SERIAL)	+= scc_sio.o
+obj-$(CONFIG_SERIAL_TXX9)	+= scc_sio.o
 obj-$(CONFIG_SPU_BASE)		+= spu_priv1.o