qcacld-3.0: Add policy attribute to SUBCMD_EXTERNAL_ACS

According to new changes in kernel 5.2 version onwards, driver has to
provide the policy for a NL command to be verified against while
registering wiphy to the kernel.

To satisfy kernel 5.2 requirement add policy to following vendor
command as part of this change:
    QCA_NL80211_VENDOR_SUBCMD_EXTERNAL_ACS

Change-Id: If2e7aec3d6f6d98168e0ceededea8d86db7078d9
CRs-Fixed: 2634255

core/hdd/src/wlan_hdd_cfg80211.c

@@ -14885,7 +14885,9 @@ const struct wiphy_vendor_command hdd_wiphy_vendor_commands[] = {
 		.flags = WIPHY_VENDOR_CMD_NEED_WDEV |
 			 WIPHY_VENDOR_CMD_NEED_NETDEV |
 			 WIPHY_VENDOR_CMD_NEED_RUNNING,
-		.doit = wlan_hdd_cfg80211_update_vendor_channel
+		.doit = wlan_hdd_cfg80211_update_vendor_channel,
+		vendor_command_policy(acs_chan_config_policy,
+				      QCA_WLAN_VENDOR_ATTR_EXTERNAL_ACS_CHANNEL_MAX)
 	},
 	{
 		.info.vendor_id = QCA_NL80211_VENDOR_ID,