bindings: python: fix uninitialized default_vals being passed to gpiod_LineBulk_request()

If "default_vals" is not provided in the kwds then default_vals are
passed uninitialized to gpiod_line_request_bulk(), so rename the
existing default_vals to vals and introduce a new default_vals that
points to vals, or NULL if no defaults have been passed.

Fixes: 96c524c4951c (bindings: implement python bindings)
Reported-by: Pedro Botella <pbotella@gmail.com>
Signed-off-by: Kent Gibson <warthog618@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
diff --git a/bindings/python/gpiodmodule.c b/bindings/python/gpiodmodule.c
index fee4c32..832787d 100644
--- a/bindings/python/gpiodmodule.c
+++ b/bindings/python/gpiodmodule.c
@@ -1327,12 +1327,13 @@
 				  NULL };
 
 	int rv, type = gpiod_LINE_REQ_DIR_AS_IS, flags = 0,
-	    default_vals[GPIOD_LINE_BULK_MAX_LINES], val;
+	    vals[GPIOD_LINE_BULK_MAX_LINES], val;
 	PyObject *def_vals_obj = NULL, *iter, *next;
 	struct gpiod_line_request_config conf;
 	struct gpiod_line_bulk bulk;
 	Py_ssize_t num_def_vals;
 	char *consumer = NULL;
+	const int *default_vals = NULL;
 	Py_ssize_t i;
 
 	if (gpiod_LineBulkOwnerIsClosed(self))
@@ -1348,7 +1349,7 @@
 	gpiod_MakeRequestConfig(&conf, consumer, type, flags);
 
 	if (def_vals_obj) {
-		memset(default_vals, 0, sizeof(default_vals));
+		memset(vals, 0, sizeof(vals));
 
 		num_def_vals = PyObject_Size(def_vals_obj);
 		if (num_def_vals != self->num_lines) {
@@ -1375,8 +1376,9 @@
 				return NULL;
 			}
 
-			default_vals[i] = !!val;
+			vals[i] = !!val;
 		}
+		default_vals = vals;
 	}
 
 	Py_BEGIN_ALLOW_THREADS;