linuxkpi: Add orderly_poweroff

This simply poweroff the system.
Needed by drm-kmod v5.8

Reviewed by:	bz
MFC after:	2 weeks
Sponsored by:	Beckhoff Automation GmbH & Co. KG
Differential Revision:	https://reviews.freebsd.org/D34287

sys/compat/linuxkpi/common/include/linux/reboot.h

@@ -0,0 +1,40 @@
+/*-
+ * Copyright (c) 2022 Beckhoff Automation GmbH & Co. KG
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#ifndef _LINUXKPI_LINUX_REBOOT_H_
+#define	_LINUXKPI_LINUX_REBOOT_H_
+
+#include <sys/reboot.h>
+
+static inline void
+orderly_poweroff(bool force)
+{
+
+	shutdown_nice(RB_POWEROFF);
+}
+
+#endif
+