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>
diff --git a/arch/arm/mach-omap2/hwinit-common.c b/arch/arm/mach-omap2/hwinit-common.c
index 3da50f9..c4a8eab 100644
--- a/arch/arm/mach-omap2/hwinit-common.c
+++ b/arch/arm/mach-omap2/hwinit-common.c
@@ -12,6 +12,7 @@
  */
 #include <common.h>
 #include <debug_uart.h>
+#include <event.h>
 #include <fdtdec.h>
 #include <init.h>
 #include <spl.h>
@@ -239,11 +240,13 @@
 }
 #endif
 
-int arch_cpu_init_dm(void)
+static int omap2_system_init(void *ctx, struct event *event)
 {
 	early_system_init();
+
 	return 0;
 }
+EVENT_SPY(EVT_DM_POST_INIT, omap2_system_init);
 
 /*
  * Routine: wait_for_command_complete