bootstd: Update bootmeth_alloc_file() to record images

As a first step to recording images and where they came from, update
this function to do so, since it is used by two bootmeths

Create a helper function in the bootflow system, since recorded
images are always associated with bootflows.

Signed-off-by: Simon Glass <sjg@chromium.org>

boot/bootflow.c

@@ -976,3 +976,24 @@ const char *bootflow_img_type_name(enum bootflow_img_t type)
 
 	return name;
 }
+
+struct bootflow_img *bootflow_img_add(struct bootflow *bflow, const char *fname,
+				      enum bootflow_img_t type, ulong addr,
+				      ulong size)
+{
+	struct bootflow_img img, *ptr;
+
+	memset(&img, '\0', sizeof(struct bootflow_img));
+	img.fname = strdup(fname);
+	if (!img.fname)
+		return NULL;
+
+	img.type = type;
+	img.addr = addr;
+	img.size = size;
+	ptr = alist_add(&bflow->images, img);
+	if (!ptr)
+		return NULL;
+
+	return ptr;
+}