netfilter: conntrack: documentation: remove reference to non-existent sysctl

The referenced sysctl doesn't exist anymore.

Fixes: 4592ee7 ("netfilter: conntrack: remove offload_pickup sysctl again")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

Author: Florian Westphal

Documentation/networking/nf_conntrack-sysctl.rst

@@ -222,11 +222,11 @@ nf_flowtable_tcp_timeout - INTEGER (seconds)
 
         Control offload timeout for tcp connections.
         TCP connections may be offloaded from nf conntrack to nf flow table.
-        Once aged, the connection is returned to nf conntrack with tcp pickup timeout.
+        Once aged, the connection is returned to nf conntrack.
 
 nf_flowtable_udp_timeout - INTEGER (seconds)
         default 30
 
         Control offload timeout for udp connections.
         UDP connections may be offloaded from nf conntrack to nf flow table.
-        Once aged, the connection is returned to nf conntrack with udp pickup timeout.
+        Once aged, the connection is returned to nf conntrack.