tipc: Fix bug in topology server byte swapping routine

This patch fixes TIPC's topology server so that it does byte swapping
correctly when endianness conversion is required.  (Note: This bug only
impacted an application if it issues a subscription request to a
topology server on another node, rather than the server on it's own
node; since the topology server is normally not accessible by off-node
applications, most TIPC applications were not impacted by the bug.)

Signed-off-by: Allan Stephens <allan.stephens@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/tipc/subscr.c

@@ -86,9 +86,7 @@ static struct top_srv topsrv = { 0 };
 
 static u32 htohl(u32 in, int swap)
 {
-	char *c = (char *)∈
-
-	return swap ? ((c[3] << 3) + (c[2] << 2) + (c[1] << 1) + c[0]) : in;
+	return swap ? (u32)___constant_swab32(in) : in;
 }
 
 /**