This NULL pointer dereference is observed during suspend resume
stress test. All pending commands are cancelled when system goes
into suspend state. There a corner case in which host may receive
response for last scan command after this and try to trigger extra
active scan for hidden SSIDs.

The issue is fixed by adding a NULL check to skip that extra scan.

Fixes: 2375fa2b (mwifiex: fix unable to connect hidden SSID..)
Cc: <stable@vger.kernel.org> [v4.2+]
Signed-off-by: Aniket Nagarnaik <aniketn@marvell.com>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>