libertas: make lbs_submit_command always 'succeed' and set command timer

Even if it fails, we want to wait a while and try again, with an
ultimate timeout if it the condition persists. So again, just use the
standard command timeout behaviour.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>