[PATCH] ieee80211: Fix iwlist scan can only show about 20 APs

Limit the amount of output given to iwlist scan.

Signed-off-by: Hong Liu <hong.liu@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>