iwlwifi: don't send GEO_TX_POWER_LIMIT if no wgds table

The GEO_TX_POWER_LIMIT command was sent although
there is no wgds table, so the fw got wrong SAR values
from the driver.

Fix this by avoiding sending the command if no wgds
tables are available.

Signed-off-by: Golan Ben Ami <golan.ben.ami@intel.com>
Fixes: 39c1a9728f ("iwlwifi: refactor the SAR tables from mvm to acpi")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Tested-By: Jonathan McDowell <noodles@earth.li>
Tested-by: Len Brown <len.brown@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/iwlwifi.20200318081237.46db40617cc6.Id5cf852ec8c5dbf20ba86bad7b165a0c828f8b2e@changeid

drivers/net/wireless/intel/iwlwifi/mvm/fw.c

@@ -762,10 +762,17 @@ static int iwl_mvm_sar_geo_init(struct iwl_mvm *mvm)
 	u16 cmd_wide_id =  WIDE_ID(PHY_OPS_GROUP, GEO_TX_POWER_LIMIT);
 	union geo_tx_power_profiles_cmd cmd;
 	u16 len;
+	int ret;
 
 	cmd.geo_cmd.ops = cpu_to_le32(IWL_PER_CHAIN_OFFSET_SET_TABLES);
 
-	iwl_sar_geo_init(&mvm->fwrt, cmd.geo_cmd.table);
+	ret = iwl_sar_geo_init(&mvm->fwrt, cmd.geo_cmd.table);
+	/*
+	 * It is a valid scenario to not support SAR, or miss wgds table,
+	 * but in that case there is no need to send the command.
+	 */
+	if (ret)
+		return 0;
 
 	cmd.geo_cmd.table_revision = cpu_to_le32(mvm->fwrt.geo_rev);