tcp: correct code comment stating 3 min timeout for FIN_WAIT2, we only do 1 min

As far as I can tell we have used a default of 60 seconds for
FIN_WAIT2 timeout for ages (since 2.x times??).

In any case, the timeout these days is 60 seconds, so the 3 min
comment is wrong (and cost me a few minutes of my life when I was
debugging a FIN_WAIT2 related problem in a userspace application and
checked the kernel source for details).

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/tcp.c

@@ -2229,7 +2229,7 @@ adjudge_to_death:
 	/*	This is a (useful) BSD violating of the RFC. There is a
 	 *	problem with TCP as specified in that the other end could
 	 *	keep a socket open forever with no application left this end.
-	 *	We use a 3 minute timeout (about the same as BSD) then kill
+	 *	We use a 1 minute timeout (about the same as BSD) then kill
 	 *	our end. If they send after that then tough - BUT: long enough
 	 *	that we won't make the old 4*rto = almost no time - whoops
 	 *	reset mistake.