r8152: fix wrong checksum status for received IPv4 packets

The device could only check the checksum of TCP and UDP packets. Therefore,
for the IPv4 packets excluding TCP and UDP, the check of checksum is necessary,
even though the IP checksum is correct.

Take ICMP for example, The IP checksum may be correct, but the ICMP checksum
may be wrong.
Signed-off-by: Hayes Wang <hayeswang@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/usb/r8152.c

@@ -1848,11 +1848,9 @@ static u8 r8152_rx_csum(struct r8152 *tp, struct rx_desc *rx_desc)
 	if (opts2 & RD_IPV4_CS) {
 		if (opts3 & IPF)
 			checksum = CHECKSUM_NONE;
-		else if ((opts2 & RD_UDP_CS) && (opts3 & UDPF))
-			checksum = CHECKSUM_NONE;
-		else if ((opts2 & RD_TCP_CS) && (opts3 & TCPF))
-			checksum = CHECKSUM_NONE;
-		else
+		else if ((opts2 & RD_UDP_CS) && !(opts3 & UDPF))
+			checksum = CHECKSUM_UNNECESSARY;
+		else if ((opts2 & RD_TCP_CS) && !(opts3 & TCPF))
 			checksum = CHECKSUM_UNNECESSARY;
 	} else if (opts2 & RD_IPV6_CS) {
 		if ((opts2 & RD_UDP_CS) && !(opts3 & UDPF))