event: Convert arch_cpu_init_dm() to use events

Instead of a special function, send an event after driver model is inited
and adjust the boards which use this function.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/init.h

@@ -45,17 +45,6 @@ void board_init_f(ulong dummy);
  */
 int arch_cpu_init(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);
-
 /**
  * mach_cpu_init() - SoC/machine dependent CPU setup
  *