BaseTools: Fix bug when converting iSCSI node

If protocol string is not specified, default TCP(0) should be used.
Today's implementation wrongly sets to 1 for this case.
Copy the fix solution from MdePkg Hash version e6c80aea.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
(cherry picked from commit c1d6749b0e)

BaseTools/Source/C/DevicePath/DevicePathFromText.c

@@ -2426,7 +2426,7 @@ DevPathFromTextiSCSI (
 
   ISCSIDevPath->LoginOption      = (UINT16) Options;
 
-  if (StrCmp (ProtocolStr, L"TCP") == 0) {
+  if (IS_NULL (*ProtocolStr) || (StrCmp (ProtocolStr, L"TCP") == 0)) {
     ISCSIDevPath->NetworkProtocol = 0;
   } else {
     //