net: thunderx: remove null check after call container_of()

container_of() will never return NULL, so remove useless code.

Signed-off-by: Haowen Bai <baihaowen@meizu.com>
Link: https://lore.kernel.org/r/1652696212-17516-1-git-send-email-baihaowen@meizu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/cavium/thunder/nicvf_main.c

@@ -2024,9 +2024,6 @@ static void nicvf_set_rx_mode_task(struct work_struct *work_arg)
 	u8 mode;
 	struct xcast_addr_list *mc;
 
-	if (!vf_work)
-		return;
-
 	/* Save message data locally to prevent them from
 	 * being overwritten by next ndo_set_rx_mode call().
 	 */