powerpc: Make powerpc pmac 32 bit build again

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

arch/powerpc/platforms/Makefile

@@ -1,4 +1,6 @@
+ifeq ($(CONFIG_PPC32),y)
 obj-$(CONFIG_PPC_PMAC)		+= powermac/
+endif
 obj-$(CONFIG_4xx)		+= 4xx/
 obj-$(CONFIG_83xx)		+= 83xx/
 obj-$(CONFIG_85xx)		+= 85xx/