acrn-config: refine board name with undline_name api

Sometimes character '-' or space need to be converted to '_' to make string format uniformed.
Add this common api to satisfy such requirment and refine the code for board name generating.

Tracked-On: #3852
Signed-off-by: Wei Liu <weix.w.liu@intel.com>
Acked-by: Victor Sun <victor.sun@intel.com>

misc/acrn-config/library/board_cfg_lib.py

@@ -460,3 +460,12 @@ def get_processor_info():
         break
 
     return tmp_list
+
+
+def undline_name(name):
+    """
+    This convert name which has contain '-' to '_'
+    :param name: name which contain '-' and ' '
+    :return: name_str which contain'_'
+    """
+    return common.undline_name(name)