ipv6: fix sparse warnings in rt6_info_hash_nhsfn()

Adding by commit 51ebd318 which adds the support of ECMP for IPv6.
Spotted-by: NFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv6/route.c

@@ -397,32 +397,32 @@ static int rt6_info_hash_nhsfn(unsigned int candidate_count,
 {
 	unsigned int val = fl6->flowi6_proto;
 
-	val ^= fl6->daddr.s6_addr32[0];
-	val ^= fl6->daddr.s6_addr32[1];
-	val ^= fl6->daddr.s6_addr32[2];
-	val ^= fl6->daddr.s6_addr32[3];
+	val ^= (__force u32)fl6->daddr.s6_addr32[0];
+	val ^= (__force u32)fl6->daddr.s6_addr32[1];
+	val ^= (__force u32)fl6->daddr.s6_addr32[2];
+	val ^= (__force u32)fl6->daddr.s6_addr32[3];
 
-	val ^= fl6->saddr.s6_addr32[0];
-	val ^= fl6->saddr.s6_addr32[1];
-	val ^= fl6->saddr.s6_addr32[2];
-	val ^= fl6->saddr.s6_addr32[3];
+	val ^= (__force u32)fl6->saddr.s6_addr32[0];
+	val ^= (__force u32)fl6->saddr.s6_addr32[1];
+	val ^= (__force u32)fl6->saddr.s6_addr32[2];
+	val ^= (__force u32)fl6->saddr.s6_addr32[3];
 
 	/* Work only if this not encapsulated */
 	switch (fl6->flowi6_proto) {
 	case IPPROTO_UDP:
 	case IPPROTO_TCP:
 	case IPPROTO_SCTP:
-		val ^= fl6->fl6_sport;
-		val ^= fl6->fl6_dport;
+		val ^= (__force u16)fl6->fl6_sport;
+		val ^= (__force u16)fl6->fl6_dport;
 		break;
 
 	case IPPROTO_ICMPV6:
-		val ^= fl6->fl6_icmp_type;
-		val ^= fl6->fl6_icmp_code;
+		val ^= (__force u16)fl6->fl6_icmp_type;
+		val ^= (__force u16)fl6->fl6_icmp_code;
 		break;
 	}
 	/* RFC6438 recommands to use flowlabel */
-	val ^= fl6->flowlabel;
+	val ^= (__force u32)fl6->flowlabel;
 
 	/* Perhaps, we need to tune, this function? */
 	val = val ^ (val >> 7) ^ (val >> 12);