net: xilinx: axienet: Always disable promiscuous mode

If promiscuous mode is disabled when there are fewer than four multicast
addresses, then it will not be reflected in the hardware. Fix this by
always clearing the promiscuous mode flag even when we program multicast
addresses.

Fixes: 8a3b7a25 ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240822154059.1066595-2-sean.anderson@linux.devSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/xilinx/xilinx_axienet_main.c

@@ -450,6 +450,10 @@ static void axienet_set_multicast_list(struct net_device *ndev)
 	} else if (!netdev_mc_empty(ndev)) {
 		struct netdev_hw_addr *ha;
 
+		reg = axienet_ior(lp, XAE_FMI_OFFSET);
+		reg &= ~XAE_FMI_PM_MASK;
+		axienet_iow(lp, XAE_FMI_OFFSET, reg);
+
 		i = 0;
 		netdev_for_each_mc_addr(ha, ndev) {
 			if (i >= XAE_MULTICAST_CAM_TABLE_NUM)