net: stmmac: dwmac4/5: Clear unused address entries

In case we don't use a given address entry we need to clear it because
it could contain previous values that are no longer valid.

Found out while running stmmac selftests.
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c

@@ -448,14 +448,20 @@ static void dwmac4_set_filter(struct mac_device_info *hw,
 		 * are required
 		 */
 		value |= GMAC_PACKET_FILTER_PR;
-	} else if (!netdev_uc_empty(dev)) {
-		int reg = 1;
+	} else {
 		struct netdev_hw_addr *ha;
+		int reg = 1;
 
 		netdev_for_each_uc_addr(ha, dev) {
 			dwmac4_set_umac_addr(hw, ha->addr, reg);
 			reg++;
 		}
+
+		while (reg <= GMAC_MAX_PERFECT_ADDRESSES) {
+			writel(0, ioaddr + GMAC_ADDR_HIGH(reg));
+			writel(0, ioaddr + GMAC_ADDR_LOW(reg));
+			reg++;
+		}
 	}
 
 	writel(value, ioaddr + GMAC_PACKET_FILTER);