powerpc/64s: Prevent fallthrough to hash TLB flush when using radix

In the fix reconnecting hash__tlb_flush() to tlb_flush() the
void return on radix__tlb_flush() was not restored and subsequently
falls through to the restored hash__tlb_flush().

Guard hash__tlb_flush() under an else to prevent this.

Fixes: 1665c027afb2 ("powerpc/64s: Reconnect tlb_flush() to hash__tlb_flush()")
Reported-by: "Erhard F." <[e-mail]>
Suggested-by: Christophe Leroy <[e-mail]>
Signed-off-by: Benjamin Gray <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/powerpc/include/asm/book3s/64/tlbflush.h

···
 {
 	if (radix_enabled())
 		radix__tlb_flush(tlb);
-
-	return hash__tlb_flush(tlb);
+	else
+		hash__tlb_flush(tlb);
 }
 
 #ifdef CONFIG_SMP