iwlwifi: mvm: don't send GEO_TX_POWER_LIMIT to old firmwares

commit eca1e56 upstream.

Old firmware versions don't support this command. Sending it
to any firmware before -41.ucode will crash the firmware.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=201975

Fixes: 66e8390 ("iwlwifi: fix wrong WGDS_WIFI_DATA_SIZE")
CC: <stable@vger.kernel.org> #4.19+
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

@@ -868,6 +868,15 @@ static int iwl_mvm_sar_geo_init(struct iwl_mvm *mvm)
  int ret, i, j;
  u16 cmd_wide_id = WIDE_ID(PHY_OPS_GROUP, GEO_TX_POWER_LIMIT);
 
+ /*
+ * This command is not supported on earlier firmware versions.
+ * Unfortunately, we don't have a TLV API flag to rely on, so
+ * rely on the major version which is in the first byte of
+ * ucode_ver.
+ */
+ if (IWL_UCODE_SERIAL(mvm->fw->ucode_ver) < 41)
+ return 0;
+
  ret = iwl_mvm_sar_get_wgds_table(mvm);
  if (ret < 0) {
  IWL_DEBUG_RADIO(mvm,