iwlwifi: move sysfs status entry to debugfs

This patch moves priv->status sysfs entry to debugfs. It is for
debugging only anyway.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>