iwlwifi: remove rfkill warning from iwl-io

The patch removes the warning since registers might be accessed also
during rfkill.

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>