iwlwifi: remove support for fw older than -17 and -22

FW versions older than -17 for 3160 and 7260 and older than -22 for
newer NICs are not supported anymore.  Don't load these versions
and remove code that handles them.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
index 8974120..8720663 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw.c
@@ -1046,19 +1046,11 @@
 {
 	struct iwl_mvm_sar_table sar_table;
 	struct iwl_dev_tx_power_cmd cmd = {
-		.v3.v2.set_mode = cpu_to_le32(IWL_TX_POWER_MODE_SET_CHAINS),
+		.v3.set_mode = cpu_to_le32(IWL_TX_POWER_MODE_SET_CHAINS),
 	};
 	int ret, i, j, idx;
 	int len = sizeof(cmd);
 
-	/* we can't do anything with the table if the FW doesn't support it */
-	if (!fw_has_api(&mvm->fw->ucode_capa,
-			IWL_UCODE_TLV_API_TX_POWER_CHAIN)) {
-		IWL_DEBUG_RADIO(mvm,
-				"FW doesn't support per-chain TX power settings.\n");
-		return 0;
-	}
-
 	if (!fw_has_capa(&mvm->fw->ucode_capa, IWL_UCODE_TLV_CAPA_TX_POWER_ACK))
 		len = sizeof(cmd.v3);