ipw2200: restart adapter only when abort_scan doesn't work

When a scan watchdog is fired, try to send abort scan command
first before restarting the adapter. This avoids reconnection for
some users when scan hang is detected.

This fixed bug https://bugzilla.kernel.org/show_bug.cgi?id=15419



Reported-by: Maurizio Avogadro <mavoga@gmail.com>
Tested-by: Maurizio Avogadro <mavoga@gmail.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>