[bug report] rtw89: add Realtek 802.11ax driver

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

Hello Ping-Ke Shih,

The patch e3ec7017f6a2: "rtw89: add Realtek 802.11ax driver" from Oct
11, 2021, leads to the following Smatch static checker warning:

	drivers/net/wireless/realtek/rtw89/fw.c:1383 rtw89_fw_h2c_rf_reg()
	error: buffer overflow 'info->rtw89_phy_config_rf_h2c' 3 <= 3

drivers/net/wireless/realtek/rtw89/phy.c
   662  static int rtw89_phy_config_rf_reg_fw(struct rtw89_dev *rtwdev,
   663                                        struct rtw89_fw_h2c_rf_reg_info *info)
   664  {
   665          u16 page = info->curr_idx / RTW89_H2C_RF_PAGE_SIZE;
   666          u16 len = (info->curr_idx % RTW89_H2C_RF_PAGE_SIZE) * 4;
   667          u8 i;
   668          int ret = 0;
   669  
   670          if (page > RTW89_H2C_RF_PAGE_NUM) {
                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Lets assume "page == RTW89_H2C_RF_PAGE_NUM.

   671                  rtw89_warn(rtwdev,
   672                             "rf reg h2c total page num %d larger than %d (RTW89_H2C_RF_PAGE_NUM)\n",
   673                             page, RTW89_H2C_RF_PAGE_NUM);
   674                  return -EINVAL;
   675          }
   676  
   677          for (i = 0; i < page; i++) {
                            ^^^^^^^^^

   678                  ret = rtw89_fw_h2c_rf_reg(rtwdev, info,
   679                                            RTW89_H2C_RF_PAGE_SIZE * 4, i);
   680                  if (ret)
   681                          return ret;
   682          }
   683          ret = rtw89_fw_h2c_rf_reg(rtwdev, info, len, i);
                                                             ^
So "i" is now RTW89_H2C_RF_PAGE_NUM and it leads to off by one out of
bounds error.

   684          if (ret)
   685                  return ret;
   686          info->curr_idx = 0;
   687  
   688          return 0;
   689  }

regards,
dan carpenter