BaseTools: fix LzmaCompress VS2013 make failure

when make BaseTools by VS2013, LzmaEnc.c report warning C4127:
conditional expression is constant, so this patch fix this issue.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

BaseTools/Source/C/LzmaCompress/Sdk/C/LzmaEnc.c

@@ -1366,8 +1366,9 @@ static UInt32 GetOptimum(CLzmaEnc *p, UInt32 position, UInt32 *backRes)
 
       if (repIndex == 0)
         startLen = lenTest + 1;
-        
+      #ifndef _MSC_VER
       if (1 /* _maxMode */)
+      #endif
         {
           UInt32 lenTest2 = lenTest + 1;
           UInt32 limit = lenTest2 + p->numFastBytes;