dm: Add a new CPU init function which can use driver model

Since driver model is set up after arch_cpu_init(), that function cannot
use drivers. Add a new arch_cpu_init_dm() function which is called
immediately after driver model is ready, and can reference devices.

This can be used to probe essential devices for the CPU.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

include/common.h

@@ -252,6 +252,17 @@ static inline int print_cpuinfo(void)
 int update_flash_size(int flash_size);
 int arch_early_init_r(void);
 
+/**
+ * arch_cpu_init_dm() - init CPU after driver model is available
+ *
+ * This is called immediately after driver model is available before
+ * relocation. This is similar to arch_cpu_init() but is able to reference
+ * devices
+ *
+ * @return 0 if OK, -ve on error
+ */
+int arch_cpu_init_dm(void);
+
 /**
  * Reserve all necessary stacks
  *