qcacmn: Add support to send candidate min roam score delta in firmware

During CU and low rssi based roam triggers, consider AP as roam candidate
only if its roam score is better than connected AP score by at least
candidate min roam score delta.

Hence, driver adds support to set candidate min roam score delta in
firmware.

Change-Id: I98d2c4ed5599e5d6d52941c46a236e0e5ccd8ba8
CRs-Fixed: 2614118

wmi/inc/wmi_unified_roam_param.h

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2019 The Linux Foundation. All rights reserved.
+ * Copyright (c) 2013-2020 The Linux Foundation. All rights reserved.
  *
  * Permission to use, copy, modify, and/or distribute this software for
  * any purpose with or without fee is hereby granted, provided that the
@@ -394,10 +394,11 @@ struct param_slot_scoring {
  * ap over the roam score of the current ap
  * @roam_trigger_bitmap: bitmap of roam triggers on which roam_score_delta
  * will be applied
+ * @vendor_roam_score_algorithm: Prefered algorithm for roam candidate selection
+ * @cand_min_roam_score_delta: candidate min roam score delta value
  * @rssi_scoring: RSSI scoring information.
  * @esp_qbss_scoring: ESP/QBSS scoring percentage information
  * @oce_wan_scoring: OCE WAN metrics percentage information
- * @vendor_roam_score_algorithm: Prefered algorithm for roam candidate selection
  */
 struct scoring_param {
 	uint32_t disable_bitmap;
@@ -418,6 +419,7 @@ struct scoring_param {
 	uint32_t roam_score_delta;
 	uint32_t roam_trigger_bitmap;
 	uint32_t vendor_roam_score_algorithm;
+	uint32_t cand_min_roam_score_delta;
 	struct rssi_scoring rssi_scoring;
 	struct param_slot_scoring esp_qbss_scoring;
 	struct param_slot_scoring oce_wan_scoring;