iwlwifi: remove obsolete lq_ready use

This patch removes the use of lq_ready, once used to sync between link
quality commands to avoid race conditions, but no longer needed as
bss_info_changed is in use.

Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
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>