Abstract value_string as common utility

Originally, we use this in scsi-lowlevel.c only, this works as static
function. It also could be used to dump ISCSI opcode, so move it into
common utils.h/utils.c.

Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>

include/utils.h

@@ -0,0 +1,37 @@
+/*
+   Utility helper functions.
+
+   Copyright (C) 2023 by zhenwei pi <pizhenwei@bytedance.com>
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU Lesser General Public License as published by
+   the Free Software Foundation; either version 2.1 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program; if not, see <http://www.gnu.org/licenses/>.
+*/
+#ifndef __iscsi_utils_h__
+#define __iscsi_utils_h__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct iscsi_value_string {
+   int value;
+   const char *string;
+};
+
+const char *iscsi_value_string_find(struct iscsi_value_string *values, int value, const char *not_found);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __iscsi_utils_h__ */