Revert "tcp: factor out __tcp_close() helper"

This reverts commit e6280603.  It is
part of a series that breaks the kernel abi for Android.  For this
kernel tree, we do not care so much about KASAN, so it's not a big issue
to revert.  If it is needed in the future, it can be brought back in an
abi-safe way.

Bug: 161946584
Change-Id: If4e4f69a51b196c752fcaa21bf7d27c971248e08
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>