HID: core: fix NULL pointer dereference

There is a NULL pointer dereference in case memory resources
for *parse* are not successfully allocated.

Fix this by adding a new goto label and make the execution
path jump to it in case vzalloc() fails.

Addresses-Coverity-ID: 1473081 ("Dereference after null check")
Fixes: b2dd9f2 ("HID: core: fix memory leak on probe")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/hid-core.c

@@ -1000,7 +1000,7 @@ int hid_open_report(struct hid_device *device)
 	parser = vzalloc(sizeof(struct hid_parser));
 	if (!parser) {
 		ret = -ENOMEM;
-		goto err;
+		goto alloc_err;
 	}
 
 	parser->device = device;
@@ -1049,6 +1049,7 @@ int hid_open_report(struct hid_device *device)
 	hid_err(device, "item fetching failed at offset %d\n", (int)(end - start));
 err:
 	kfree(parser->collection_stack);
+alloc_err:
 	vfree(parser);
 	hid_close_report(device);
 	return ret;