event: Convert misc_init_f() to use events

This hook can be implmented using events, for the three boards that
actually use it.

Add the event type and event handlers. Drop CONFIG_MISC_INIT_F since we
can just use CONFIG_EVENT to control this. Since sandbox always enables
CONFIG_EVENT, we can drop the defconfig lines there too.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/keymile/pg-wcom-ls102xa/pg-wcom-ls102xa.c b/board/keymile/pg-wcom-ls102xa/pg-wcom-ls102xa.c
index 467f110..ed8142d 100644
--- a/board/keymile/pg-wcom-ls102xa/pg-wcom-ls102xa.c
+++ b/board/keymile/pg-wcom-ls102xa/pg-wcom-ls102xa.c
@@ -4,6 +4,7 @@
  */
 
 #include <common.h>
+#include <event.h>
 #include <i2c.h>
 #include <asm/io.h>
 #include <asm/arch/immap_ls102xa.h>
@@ -109,12 +110,14 @@
 	return 0;
 }
 
-int misc_init_f(void)
+static int pg_wcom_misc_init_f(void *ctx, struct event *event)
 {
 	if (IS_ENABLED(CONFIG_PG_WCOM_UBOOT_UPDATE_SUPPORTED))
 		check_for_uboot_update();
+
 	return 0;
 }
+EVENT_SPY(EVT_MISC_INIT_F, pg_wcom_misc_init_f);
 
 int board_init(void)
 {