iwlwifi: mvm: fix old scan version sizes

When version 8 of the scan command API was introduced, only the size
of version 7 was updated, causing older versions of the firmware to
throw BAD_COMMAND errors.

Calculating the old version based on the size of the latest version
got too complicated and the size of the older versions will never
change anyway, so it's better to just hardcoded the sizes.

Fixes: 66fa2424 ("iwlwifi: fw api: support the new scan request FW API version")
Reported-by: Scott Register <sreg@sreg.io>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/intel/iwlwifi/fw/api/scan.h

@@ -8,6 +8,7 @@
  * Copyright(c) 2012 - 2014 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
  * Copyright(c) 2016 - 2017 Intel Deutschland GmbH
+ * Copyright(c) 2018        Intel Corporation
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of version 2 of the GNU General Public License as
@@ -749,13 +750,9 @@ struct iwl_scan_req_umac {
 } __packed;
 
 #define IWL_SCAN_REQ_UMAC_SIZE_V8 sizeof(struct iwl_scan_req_umac)
-#define IWL_SCAN_REQ_UMAC_SIZE_V7 (sizeof(struct iwl_scan_req_umac) - \
-					 4 * sizeof(u8))
-#define IWL_SCAN_REQ_UMAC_SIZE_V6 (sizeof(struct iwl_scan_req_umac) - \
-				   2 * sizeof(u8) - sizeof(__le16))
-#define IWL_SCAN_REQ_UMAC_SIZE_V1 (sizeof(struct iwl_scan_req_umac) - \
-				   2 * sizeof(__le32) - 2 * sizeof(u8) - \
-				   sizeof(__le16))
+#define IWL_SCAN_REQ_UMAC_SIZE_V7 48
+#define IWL_SCAN_REQ_UMAC_SIZE_V6 44
+#define IWL_SCAN_REQ_UMAC_SIZE_V1 36
 
 /**
  * struct iwl_umac_scan_abort