[bug report] iwlwifi: Add support for SAR South Korea limitation

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Haim Dreyfuss,

The patch 0c3d7282233c: "iwlwifi: Add support for SAR South Korea
limitation" from Feb 27, 2019, leads to the following static checker
warning:

	drivers/net/wireless/intel/iwlwifi/fw/acpi.c:166 iwl_acpi_get_mcc()
	warn: passing a valid pointer to 'PTR_ERR'

drivers/net/wireless/intel/iwlwifi/fw/acpi.c
   153  int iwl_acpi_get_mcc(struct device *dev, char *mcc)
   154  {
   155          union acpi_object *wifi_pkg, *data;
   156          u32 mcc_val;
   157          int ret, tbl_rev;
   158  
   159          data = iwl_acpi_get_object(dev, ACPI_WRDD_METHOD);
   160          if (IS_ERR(data))
   161                  return PTR_ERR(data);
   162  
   163          wifi_pkg = iwl_acpi_get_wifi_pkg(dev, data, ACPI_WRDD_WIFI_DATA_SIZE,
   164                                           &tbl_rev);
   165          if (IS_ERR(wifi_pkg) || tbl_rev != 0) {
                                        ^^^^^^^^^^^^
wifi_pkg is not a valid error code.  Also it feels like it might be more
future proof to blacklist rev 1 instead of whitelisting rev 0.

   166                  ret = PTR_ERR(wifi_pkg);
   167                  goto out_free;
   168          }
   169  
   170          if (wifi_pkg->package.elements[1].type != ACPI_TYPE_INTEGER) {
   171                  ret = -EINVAL;
   172                  goto out_free;
   173          }
   174  
   175          mcc_val = wifi_pkg->package.elements[1].integer.value;
   176  
   177          mcc[0] = (mcc_val >> 8) & 0xff;
   178          mcc[1] = mcc_val & 0xff;
   179          mcc[2] = '\0';
   180  
   181          ret = 0;
   182  out_free:
   183          kfree(data);
   184          return ret;
   185  }

regards,
dan carpenter