net: tcp: Only return -ETIMEDOUT if timeout>0 in connect

No need to set the status to -ETIMEDOUT in connect callback
if user did not want to have a timeout when doing a TCP connect.

Change-Id: I6d6e565a8d12bcefbcd9de751e789b5e43aad244
Signed-off-by: Jukka Rissanen <jukka.rissanen@linux.intel.com>