net: stmmac: dwmac1000: fix out-of-bounds mac address reg setting

Commit 9463c44559 ("net: stmmac: dwmac1000: Clear unused address
entries") cleared the unused mac address entries, but introduced an
out-of bounds mac address register programming bug -- After setting
the secondary unicast mac addresses, the "reg" value has reached
netdev_uc_count() + 1, thus we should only clear address entries
if (addr < perfect_addr_number)

Fixes: 9463c44559 ("net: stmmac: dwmac1000: Clear unused address entries")
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac1000_core.c

@@ -207,7 +207,7 @@ static void dwmac1000_set_filter(struct mac_device_info *hw,
 			reg++;
 		}
 
-		while (reg <= perfect_addr_number) {
+		while (reg < perfect_addr_number) {
 			writel(0, ioaddr + GMAC_ADDR_HIGH(reg));
 			writel(0, ioaddr + GMAC_ADDR_LOW(reg));
 			reg++;