powerpc/book3e/kdump: Enable crash_kexec_wait_realmode

While book3e doesn't have "real mode", we still want to wait for
all the non-crash cpus to complete their shutdown.
Signed-off-by: Scott Wood <scottwood@freescale.com>

arch/powerpc/kernel/crash.c

@@ -221,8 +221,8 @@ void crash_kexec_secondary(struct pt_regs *regs)
 #endif	/* CONFIG_SMP */
 
 /* wait for all the CPUs to hit real mode but timeout if they don't come in */
-#if defined(CONFIG_SMP) && defined(CONFIG_PPC_STD_MMU_64)
-static void crash_kexec_wait_realmode(int cpu)
+#if defined(CONFIG_SMP) && defined(CONFIG_PPC64)
+static void __maybe_unused crash_kexec_wait_realmode(int cpu)
 {
 	unsigned int msecs;
 	int i;
@@ -244,7 +244,7 @@ static void crash_kexec_wait_realmode(int cpu)
 }
 #else
 static inline void crash_kexec_wait_realmode(int cpu) {}
-#endif	/* CONFIG_SMP && CONFIG_PPC_STD_MMU_64 */
+#endif	/* CONFIG_SMP && CONFIG_PPC64 */
 
 /*
  * Register a function to be called on shutdown.  Only use this if you