[IPV6]: Fix several comment spelling errors and typos.

net/ipv6/addrconf.c

@@ -1338,7 +1338,7 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len)
 	 *	2) Configure prefixes with the auto flag set
 	 */
 
-	/* Avoid arithemtic overflow. Really, we could
+	/* Avoid arithmetic overflow. Really, we could
 	   save rt_expires in seconds, likely valid_lft,
 	   but it would require division in fib gc, that it
 	   not good.

net/ipv6/exthdrs.c

@@ -367,7 +367,7 @@ ipv6_invert_rthdr(struct sock *sk, struct ipv6_rt_hdr *hdr)
 	   Inverted result:
 	   [ H_prev -> ... -> H1 ] daddr =sender
 
-	   Note, that IP output engine will rewrire this rthdr
+	   Note, that IP output engine will rewrite this rthdr
 	   by rotating it left by one addr.
 	 */
 

net/ipv6/ip6_fib.c

@@ -942,7 +942,7 @@ static void fib6_del_route(struct fib6_node *fn, struct rt6_info **rtp,
 			}
 			fn = fn->parent;
 		}
-		/* No more references are possiible at this point. */
+		/* No more references are possible at this point. */
 		if (atomic_read(&rt->rt6i_ref) != 1) BUG();
 	}
 

net/ipv6/reassembly.c

@@ -526,7 +526,7 @@ static void ip6_frag_queue(struct frag_queue *fq, struct sk_buff *skb,
 		} else {
 			struct sk_buff *free_it = next;
 
-			/* Old fragmnet is completely overridden with
+			/* Old fragment is completely overridden with
 			 * new one drop it.
 			 */
 			next = next->next;

net/ipv6/route.c

@@ -785,7 +785,7 @@ int ip6_route_add(struct in6_rtmsg *rtmsg, struct nlmsghdr *nlh, void *_rtattr)
 			/* IPv6 strictly inhibits using not link-local
 			   addresses as nexthop address.
 			   Otherwise, router will not able to send redirects.
-			   It is very good, but in some (rare!) curcumstances
+			   It is very good, but in some (rare!) circumstances
 			   (SIT, PtP, NBMA NOARP links) it is handy to allow
 			   some exceptions. --ANK
 			 */
@@ -1365,10 +1365,10 @@ static int rt6_mtu_change_route(struct rt6_info *rt, void *p_arg)
 	 */
 	/*
 	   If new MTU is less than route PMTU, this new MTU will be the
-	   lowest MTU in the path, update the route PMTU to refect PMTU
+	   lowest MTU in the path, update the route PMTU to reflect PMTU
 	   decreases; if new MTU is greater than route PMTU, and the
 	   old MTU is the lowest MTU in the path, update the route PMTU
-	   to refect the increase. In this case if the other nodes' MTU
+	   to reflect the increase. In this case if the other nodes' MTU
 	   also have the lowest MTU, TOO BIG MESSAGE will be lead to
 	   PMTU discouvery.
 	 */