ppc64: set MSR_SF bit

When a qemu-system-ppc64 is started, the 64-bit mode bit
is not set in MSR.
Signed-off-by: NLaurent Vivier <lvivier@redhat.com>
Reviewed-by: NAlexander Graf <agraf@suse.de>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

target-ppc/translate_init.c

@@ -9703,7 +9703,7 @@ static void ppc_cpu_reset(CPUState *s)
 
 #if defined(TARGET_PPC64)
     if (env->mmu_model & POWERPC_MMU_64) {
-        env->msr |= (1ULL << MSR_SF);
+        msr |= (1ULL << MSR_SF);
     }
 #endif