[PATCH] assoc_array: Mark expected switch fall-through

["Gustavo A. R. Silva" <gustavo@embeddedor.com>]

In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.

This patch fixes the following warning:

lib/assoc_array.c: In function ‘assoc_array_delete’:
lib/assoc_array.c:1110:3: warning: this statement may fall through [-Wimplicit-fallthrough=]
   for (slot = 0; slot < ASSOC_ARRAY_FAN_OUT; slot++) {
   ^~~
lib/assoc_array.c:1118:2: note: here
  case assoc_array_walk_tree_empty:
  ^~~~

Warning level 3 was used: -Wimplicit-fallthrough=3

This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 lib/assoc_array.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/assoc_array.c b/lib/assoc_array.c
index c6659cb37033..0b61d3b77e5c 100644
--- a/lib/assoc_array.c
+++ b/lib/assoc_array.c
@@ -1115,6 +1115,7 @@ struct assoc_array_edit *assoc_array_delete(struct assoc_array *array,
 						index_key))
 				goto found_leaf;
 		}
+		/* fall through */
 	case assoc_array_walk_tree_empty:
 	case assoc_array_walk_found_wrong_shortcut:
 	default:
-- 
2.20.1