powerpc: ppc32 clean up available memory models

Clean up the currently available memory models for ppc32.  It seems
that we do need FLATMEM for ppc32 on non-NUMA.  It also seems that
SPARSEMEM is not parameterised yet so disable that.

Signed-off-by: Andy Whitcroft <apw@shadwen.org>
---
diff -upN reference/arch/powerpc/Kconfig current/arch/powerpc/Kconfig
--- reference/arch/powerpc/Kconfig
+++ current/arch/powerpc/Kconfig
@@ -584,14 +584,15 @@ config ARCH_SELECT_MEMORY_MODEL
 
 config ARCH_FLATMEM_ENABLE
        def_bool y
-       depends on PPC64 && !NUMA
+       depends on !NUMA
 
 config ARCH_SPARSEMEM_ENABLE
 	def_bool y
+	depends on PPC64
 
 config ARCH_SPARSEMEM_DEFAULT
 	def_bool y
-	depends on SMP && PPC_PSERIES
+	depends on SMP && PPC_PSERIES && NUMA
 
 source "mm/Kconfig"