powerpc/pseries: Always enable SMP when building pseries

The pseries platform supports Power4 and later CPUs, all of which are
multithreaded and/or multicore.

In practice no one ever builds a SMP=n kernel for these machines. So as
we did for powernv, have the pseries platform imply SMP=y.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/pseries/Kconfig

@@ -17,9 +17,10 @@ config PPC_PSERIES
 	select PPC_UDBG_16550
 	select PPC_NATIVE
 	select PPC_DOORBELL
-	select HOTPLUG_CPU if SMP
+	select HOTPLUG_CPU
 	select ARCH_RANDOM
 	select PPC_DOORBELL
+	select FORCE_SMP
 	default y
 
 config PPC_SPLPAR