WinCE5.0 Support 4GB SD Card On MainstoneII

1. 安裝WinCEPB50-070430-2007M04-Armv4I.msi patch，
   內含SDHC(KB933809)更新。 讓WinCE可支援SD High Capacity Card(4GB~32GB)
2. 增加IMGSDBUS2=1環境變數，enable SD BUS 2支援。
3. 修改Mainstone SDHC driver，如下：
   增加ResponseR7 support至sdcontrol.c檔，底下為部份程式碼。
   switch (pRequest->CommandResponse.ResponseType) {
       case NoResponse:
          cmdatRegister = MMC_CMDAT_RESPONSE_NONE;
       break;
   
       case ResponseR1b:
          // response1 with busy signaling
          cmdatRegister = MMC_CMDAT_RESPONSE_R1;
       break;
   
       case ResponseR1:
          ......
          ......
   
       case ResponseR7:
          // on an MMC controller R5 and R6 are really just an R1 response
          cmdatRegister = MMC_CMDAT_RESPONSE_R1;
       break;
   
       case ResponseR2:
          cmdatRegister = MMC_CMDAT_RESPONSE_R2;
       break;
       ......
       ......
      return SD_API_STATUS_INVALID_PARAMETER;