MdeModulePkg SdBlockIoPei: Initialize 'SwitchResp' elements before using

The commit makes sure that the elements in array 'SwitchResp' get
initialized before being used.

Cc: Feng Tian <feng.tian@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

MdeModulePkg/Bus/Sd/SdBlockIoPei/SdHci.c

@@ -2647,6 +2647,7 @@ SdPeimSetBusMode (
   //
   // Get the supported bus speed from SWITCH cmd return data group #1.
   //
+  ZeroMem (SwitchResp, sizeof (SwitchResp));
   Status = SdPeimSwitch (Slot, 0xF, 0xF, 0xF, 0xF, FALSE, SwitchResp);
   if (EFI_ERROR (Status)) {
     return Status;