selftests: netfilter: nft_flowtable.sh: bump socat timeout to 1m

Now that this test runs in netdev CI it looks like 10s isn't enough
for debug kernels:
  selftests: net/netfilter: nft_flowtable.sh
  2024/05/10 20:33:08 socat[12204] E write(7, 0x563feb16a000, 8192): Broken pipe
  FAIL: file mismatch for ns1 -> ns2
  -rw------- 1 root root 37345280 May 10 20:32 /tmp/tmp.Am0yEHhNqI
 ...

Looks like socat gets zapped too quickly, so increase timeout to 1m.

Could also reduce tx file size for KSFT_MACHINE_SLOW, but its preferrable
to have same test for both debug and nondebug.
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/r/20240511064814.561525-1-fw@strlen.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/net/netfilter/nft_flowtable.sh

@@ -17,6 +17,7 @@
 source lib.sh
 
 ret=0
+SOCAT_TIMEOUT=60
 
 nsin=""
 ns1out=""
@@ -350,12 +351,12 @@ test_tcp_forwarding_ip()
 	local dstport=$4
 	local lret=0
 
-	timeout 10 ip netns exec "$nsb" socat -4 TCP-LISTEN:12345,reuseaddr STDIO < "$nsin" > "$ns2out" &
+	timeout "$SOCAT_TIMEOUT" ip netns exec "$nsb" socat -4 TCP-LISTEN:12345,reuseaddr STDIO < "$nsin" > "$ns2out" &
 	lpid=$!
 
 	busywait 1000 listener_ready
 
-	timeout 10 ip netns exec "$nsa" socat -4 TCP:"$dstip":"$dstport" STDIO < "$nsin" > "$ns1out"
+	timeout "$SOCAT_TIMEOUT" ip netns exec "$nsa" socat -4 TCP:"$dstip":"$dstport" STDIO < "$nsin" > "$ns1out"
 
 	wait $lpid