udp: Fix typo in net/ipv4/udp.c

Signed-off-by: NSu Yanjun <suyj.fnst@cn.fujitsu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/udp.c

@@ -2170,7 +2170,7 @@ static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
 
 /* Initialize UDP checksum. If exited with zero value (success),
  * CHECKSUM_UNNECESSARY means, that no more checks are required.
- * Otherwise, csum completion requires chacksumming packet body,
+ * Otherwise, csum completion requires checksumming packet body,
  * including udp header and folding it to skb->csum.
  */
 static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,