net: Remove casts to same type

Adding casts of objects to the same type is unnecessary
and confusing for a human reader.

For example, this cast:

	int y;
	int *p = (int *)&y;

I used the coccinelle script below to find and remove these
unnecessary casts.  I manually removed the conversions this
script produces of casts with __force and __user.

@@
type T;
T *p;
@@

-	(T *)p
+	p

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 6447dc4..fa3d9c3 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -791,14 +791,14 @@
 		if (ohdr) {
 			memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
 			*hdr = (struct ipv6_opt_hdr *)*p;
-			*p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
+			*p += CMSG_ALIGN(ipv6_optlen(*hdr));
 		}
 	} else {
 		if (newopt) {
 			if (copy_from_user(*p, newopt, newoptlen))
 				return -EFAULT;
 			*hdr = (struct ipv6_opt_hdr *)*p;
-			if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
+			if (ipv6_optlen(*hdr) > newoptlen)
 				return -EINVAL;
 			*p += CMSG_ALIGN(newoptlen);
 		}