[MIPS] Rename _machine_power_off to pm_power_off so the kernel builds again.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

include/asm-mips/reboot.h

@@ -3,7 +3,7 @@
  * License.  See the file "COPYING" in the main directory of this archive
  * for more details.
  *
- * Copyright (C) 1997, 1999, 2001 by Ralf Baechle
+ * Copyright (C) 1997, 1999, 2001, 06 by Ralf Baechle
  * Copyright (C) 2001 MIPS Technologies, Inc.
  */
 #ifndef _ASM_REBOOT_H
@@ -11,6 +11,5 @@
 
 extern void (*_machine_restart)(char *command);
 extern void (*_machine_halt)(void);
-extern void (*_machine_power_off)(void);
 
 #endif /* _ASM_REBOOT_H */