powerpc: Enable kernel XZ compression option on BOOK3S_32

Enable kernel XZ compression option on BOOK3S_32. Tested on G4
PowerBook.
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
[mpe: Use one select under the PPC symbol guarded by if PPC_BOOK3S]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/Kconfig

@@ -197,6 +197,7 @@ config PPC
 	select HAVE_IOREMAP_PROT
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK
 	select HAVE_KERNEL_GZIP
+	select HAVE_KERNEL_XZ			if PPC_BOOK3S
 	select HAVE_KPROBES
 	select HAVE_KPROBES_ON_FTRACE
 	select HAVE_KRETPROBES

arch/powerpc/platforms/Kconfig.cputype

@@ -74,7 +74,6 @@ config PPC_BOOK3S_64
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select ARCH_SUPPORTS_NUMA_BALANCING
 	select IRQ_WORK
-	select HAVE_KERNEL_XZ
 
 config PPC_BOOK3E_64
 	bool "Embedded processors"