tcp: whitespace fixes

Fix places where there is space before tab, long lines, and
awkward if(){, double spacing etc. Add blank line after declaration/initialization.

Change-Id: I81274eee2a65c8ea788f9b6301f27e794a12bb17
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Albert I <krascgq@outlook.co.id>