usb: gadget: mass_storage: Free buffers if create lun fails

Creation of LUN 0 may fail (for example due to ENOMEM).
As fsg_common_set_num_buffers() does some memory allocation
we should free it before it becomes unavailable.
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/function/f_mass_storage.c

@@ -3524,6 +3524,9 @@ static struct usb_function_instance *fsg_alloc_inst(void)
 	config.removable = true;
 	rc = fsg_common_create_lun(opts->common, &config, 0, "lun.0",
 			(const char **)&opts->func_inst.group.cg_item.ci_name);
+	if (rc)
+		goto release_buffers;
+
 	opts->lun0.lun = opts->common->luns[0];
 	opts->lun0.lun_id = 0;
 	config_group_init_type_name(&opts->lun0.group, "lun.0", &fsg_lun_type);
@@ -3534,6 +3537,8 @@ static struct usb_function_instance *fsg_alloc_inst(void)
 
 	return &opts->func_inst;
 
+release_buffers:
+	fsg_common_free_buffers(opts->common);
 release_luns:
 	kfree(opts->common->luns);
 release_opts: