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/configs/pg_wcom_seli8_defconfig b/configs/pg_wcom_seli8_defconfig
index 8ca1a60..bca0163 100644
--- a/configs/pg_wcom_seli8_defconfig
+++ b/configs/pg_wcom_seli8_defconfig
@@ -35,6 +35,7 @@
 CONFIG_USE_BOOTARGS=y
 CONFIG_BOOTARGS="console=ttyS0,115200 root=/dev/ram0"
 CONFIG_SILENT_CONSOLE=y
+CONFIG_EVENT=y
 CONFIG_LAST_STAGE_INIT=y
 CONFIG_MISC_INIT_R=y
 CONFIG_CMD_IMLS=y