The function ipw_request_direct_scan() should bail out when the device
is down.  This fixes a lockup caused by wpa_supplicant triggering
ipw_request_direct_scan() while the driver was in a middle of a reset
due to firmware errors.

Thanks to Zilvinas Valinskas for reporting the bug and helping me
debug it.
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NZhu Yi <yi.zhu@intel.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>