MIPS: malta: remove unused header file

Remove unused heasder file asm/mach-malta/malta-pm.h.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

arch/mips/include/asm/mach-malta/malta-pm.h

-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * Copyright (C) 2014 Imagination Technologies
- * Author: Paul Burton <paul.burton@mips.com>
- */
-
-#ifndef __ASM_MIPS_MACH_MALTA_PM_H__
-#define __ASM_MIPS_MACH_MALTA_PM_H__
-
-#include <asm/mips-boards/piix4.h>
-
-#ifdef CONFIG_MIPS_MALTA_PM
-
-/**
- * mips_pm_suspend - enter a suspend state
- * @state: the state to enter, one of PIIX4_FUNC3IO_PMCNTRL_SUS_TYP_*
- *
- * Enters a suspend state via the Malta's PIIX4. If the state to be entered
- * is one which loses context (eg. SOFF) then this function will never
- * return.
- */
-extern int mips_pm_suspend(unsigned state);
-
-#else /* !CONFIG_MIPS_MALTA_PM */
-
-static inline int mips_pm_suspend(unsigned state)
-{
-	return -EINVAL;
-}
-
-#endif /* !CONFIG_MIPS_MALTA_PM */
-
-#endif /* __ASM_MIPS_MACH_MALTA_PM_H__ */