kconfig: annotate non-trivial fall-trough

Signed-off-by: Arnaud Lacombe <lacombar@gmail.com>
diff --git a/scripts/kconfig/conf.c b/scripts/kconfig/conf.c
index 006ad817..6d2e936 100644
--- a/scripts/kconfig/conf.c
+++ b/scripts/kconfig/conf.c
@@ -106,6 +106,7 @@
 			return 0;
 		}
 		check_stdin();
+		/* fall through */
 	case oldaskconfig:
 		fflush(stdout);
 		xfgets(line, 128, stdin);
@@ -150,6 +151,7 @@
 				def = NULL;
 				break;
 			}
+			/* fall through */
 		default:
 			line[strlen(line)-1] = 0;
 			def = line;
@@ -304,6 +306,7 @@
 				break;
 			}
 			check_stdin();
+			/* fall through */
 		case oldaskconfig:
 			fflush(stdout);
 			xfgets(line, 128, stdin);
@@ -369,6 +372,7 @@
 				check_conf(menu);
 				return;
 			}
+			/* fall through */
 		case P_COMMENT:
 			prompt = menu_get_prompt(menu);
 			if (prompt)