Added validation for BB offset parameter

Author: bbogush

qt/parallel_chip_db_table_model.cpp

@@ -381,6 +381,8 @@ bool ParallelChipDbTableModel::setData(const QModelIndex &index,
     case ParallelChipDb::CHIP_PARAM_BB_MARK_OFF:
         if (chipDb->getParamFromString(value.toString(), paramVal))
             return false;
+        if (chipDb->isParamValid(paramVal, 0, 0xFF))
+            return false;
         chipDb->setBBMarkOffset(index.row(), paramVal);
         return true;
     case ParallelChipDb::CHIP_PARAM_T_CS: