powerpc/64s: Enhance the information in cpu_show_meltdown()

Now that we have the security feature flags we can make the
information displayed in the "meltdown" file more informative.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/include/asm/security_features.h b/arch/powerpc/include/asm/security_features.h
index db00ad2..400a905 100644
--- a/arch/powerpc/include/asm/security_features.h
+++ b/arch/powerpc/include/asm/security_features.h
@@ -10,6 +10,7 @@
 
 
 extern unsigned long powerpc_security_features;
+extern bool rfi_flush;
 
 static inline void security_ftr_set(unsigned long feature)
 {