iwlwifi: trigger scan synchronously

Scan requesting doesn't need to be asynchronous
since all code paths leading up to it can sleep.
Make the scan request a new util operation that
is hw-specific (to account for 3945 vs. agn)
and call it right in place.

This patch moves a lot of code into iwlagn as
it need not be in iwlcore.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.h b/drivers/net/wireless/iwlwifi/iwl-agn.h
index 5d31422..cfee999 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.h
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.h
@@ -171,4 +171,7 @@
 	       (status == TX_STATUS_DIRECT_DONE);
 }
 
+/* scan */
+void iwlagn_request_scan(struct iwl_priv *priv);
+
 #endif /* __iwl_agn_h__ */