sh: add SMP method selection to device tree pseudo-board

Allow selection of plat_smp_ops based on the enable-method cpu
property from device tree and provide dummy ops for booting with a
device tree that does not enable SMP.

Signed-off-by: Rich Felker <dalias@libc.org>

arch/sh/include/asm/smp.h

@@ -69,6 +69,16 @@ static inline int hard_smp_processor_id(void)
 	return mp_ops->smp_processor_id();
 }
 
+struct of_cpu_method {
+	const char *method;
+	struct plat_smp_ops *ops;
+};
+
+#define CPU_METHOD_OF_DECLARE(name, _method, _ops)			\
+	static const struct of_cpu_method __cpu_method_of_table_##name	\
+		__used __section(__cpu_method_of_table)			\
+		= { .method = _method, .ops = _ops }
+
 #else
 
 #define hard_smp_processor_id()	(0)