BaseTools: Increase the DevicePath length for support more PCD value.

Currently the PCD Value only support 13 Guid,When use more 13 pcd will cause the build tool fail,
Need calculate the required memory,then allocate it.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3718

Cc: Bob Feng <bob.c.feng@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Yuwei Chen <yuwei.chen@intel.com>

Signed-off-by: Xiaolu Jiang <xiaolu.jiang@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Source/C/DevicePath/DevicePath.c

@@ -170,7 +170,7 @@ int main(int argc, CHAR8 *argv[])
     fprintf(stderr, "Invalid option value, Device Path can't be NULL");
     return STATUS_ERROR;
   }
-  Str16 = (CHAR16 *)malloc(1024);
+  Str16 = (CHAR16 *)malloc((strlen (Str) + 1) * sizeof (CHAR16));
   if (Str16 == NULL) {
     fprintf(stderr, "Resource, memory cannot be allocated");
     return STATUS_ERROR;