powerpc/64: Call setup_barrier_nospec() from setup_arch()

Currently we require platform code to call setup_barrier_nospec(). But
if we add an empty definition for the !CONFIG_PPC_BARRIER_NOSPEC case
then we can call it in setup_arch().

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/pseries/setup.c

@@ -551,7 +551,6 @@ void pseries_setup_rfi_flush(void)
 		 security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR);
 
 	setup_rfi_flush(types, enable);
-	setup_barrier_nospec();
 }
 
 #ifdef CONFIG_PCI_IOV