drm/rockchip: vop2: use struct_size() in vop2_bind

Use the overflow-protected struct_size() helper macro to compute the
allocation size of the vop2 data structure.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Cc: Sandy Huang <hjc@rock-chips.com>
Cc: Heiko Stübner <heiko@sntech.de>
Cc: David Airlie <airlied@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230223013533.1707706-1-jacob.e.keller@intel.com

drivers/gpu/drm/rockchip/rockchip_drm_vop2.c

@@ -2655,7 +2655,7 @@ static int vop2_bind(struct device *dev, struct device *master, void *data)
 		return -ENODEV;
 
 	/* Allocate vop2 struct and its vop2_win array */
-	alloc_size = sizeof(*vop2) + sizeof(*vop2->win) * vop2_data->win_size;
+	alloc_size = struct_size(vop2, win, vop2_data->win_size);
 	vop2 = devm_kzalloc(dev, alloc_size, GFP_KERNEL);
 	if (!vop2)
 		return -ENOMEM;