iwlwifi: dvm: clear IWL_STA_UCODE_INPROGRESS when assoc fails

We set IWL_STA_UCODE_INPROGRESS flag when we add a station
and clear it when we send the LQ command for it. But the LQ
command is sent only when the association succeeds.
If the association doesn't succeed, we would leave this flag
set and that wouldn't indicate the station entry as vacant.

This probably fixes:
https://bugzilla.redhat.com/show_bug.cgi?id=1065663

Cc: <stable@vger.kernel.org>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>