iwlwifi: fix fw version reading for DVM devices

In commit 97f95c93 ("iwlwifi: remove support for fw older than
-16.ucode") we accidentally changed the fw version reading code for
DVM devices.  The code intended to remove the old fw version API,
because all MVM firmwares version 16 and above that we support don't
use it anymore.  But DVM devices still use the old FW API.

Fix that by bringing the code back in.
Reported-by: Pat Erley <pat-lkml@erley.org>
Tested-by: Kalle Valo <kvalo@codeaurora.org>
Fixes: 97f95c93 ("iwlwifi: remove support for fw older than-16.ucode")
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/intel/iwlwifi/iwl-drv.c

@@ -1280,7 +1280,10 @@ static void iwl_req_fw_callback(const struct firmware *ucode_raw, void *context)
 	if (err)
 		goto try_again;
 
-	api_ver = drv->fw.ucode_ver;
+	if (fw_has_api(&drv->fw.ucode_capa, IWL_UCODE_TLV_API_NEW_VERSION))
+		api_ver = drv->fw.ucode_ver;
+	else
+		api_ver = IWL_UCODE_API(drv->fw.ucode_ver);
 
 	/*
 	 * api_ver should match the api version forming part of the

drivers/net/wireless/intel/iwlwifi/iwl-fw-file.h

@@ -251,6 +251,7 @@ typedef unsigned int __bitwise__ iwl_ucode_tlv_api_t;
  * @IWL_UCODE_TLV_API_WIFI_MCC_UPDATE: ucode supports MCC updates with source.
  * @IWL_UCODE_TLV_API_WIDE_CMD_HDR: ucode supports wide command header
  * @IWL_UCODE_TLV_API_LQ_SS_PARAMS: Configure STBC/BFER via LQ CMD ss_params
+ * @IWL_UCODE_TLV_API_NEW_VERSION: new versioning format
  * @IWL_UCODE_TLV_API_EXT_SCAN_PRIORITY: scan APIs use 8-level priority
  *	instead of 3.
  * @IWL_UCODE_TLV_API_TX_POWER_CHAIN: TX power API has larger command size
@@ -263,6 +264,7 @@ enum iwl_ucode_tlv_api {
 	IWL_UCODE_TLV_API_WIFI_MCC_UPDATE	= (__force iwl_ucode_tlv_api_t)9,
 	IWL_UCODE_TLV_API_WIDE_CMD_HDR		= (__force iwl_ucode_tlv_api_t)14,
 	IWL_UCODE_TLV_API_LQ_SS_PARAMS		= (__force iwl_ucode_tlv_api_t)18,
+	IWL_UCODE_TLV_API_NEW_VERSION           = (__force iwl_ucode_tlv_api_t)20,
 	IWL_UCODE_TLV_API_EXT_SCAN_PRIORITY	= (__force iwl_ucode_tlv_api_t)24,
 	IWL_UCODE_TLV_API_TX_POWER_CHAIN	= (__force iwl_ucode_tlv_api_t)27,