BaseTools/TianoCompress: Add checks for array access

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

BaseTools/Source/C/TianoCompress/TianoCompress.c

@@ -2215,7 +2215,7 @@ Returns:
   for (Char = 0; Char < NumOfChar; Char++) {
 
     Len = BitLen[Char];
-    if (Len == 0) {
+    if (Len == 0 || Len >= 17) {
       continue;
     }
 
@@ -2346,6 +2346,8 @@ Returns:
   volatile UINT16  Index;
   UINT32  Mask;
 
+  assert (nn <= NPT);
+
   Number = (UINT16) GetBits (Sd, nbit);
 
   if (Number == 0) {