expo: Add CLI context to the expo

An expo generally needs to keep track of the keyboard state while it is
running, so move the context into struct expo

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/boot/expo.c b/boot/expo.c
index 8ce645e..9c042f1 100644
--- a/boot/expo.c
+++ b/boot/expo.c
@@ -30,6 +30,7 @@
 	INIT_LIST_HEAD(&exp->scene_head);
 	INIT_LIST_HEAD(&exp->str_head);
 	exp->next_id = EXPOID_BASE_ID;
+	cli_ch_init(&exp->cch);
 
 	*expp = exp;