ARM: at91: remove unused mach/system_rev.h

mach/system_rev.h is not used, remove it.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/mach-at91/include/mach/system_rev.h

-/*
- * Copyright (C) 2011 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
- *
- * Under GPLv2 only
- */
-
-#ifndef __ARCH_SYSTEM_REV_H__
-#define __ARCH_SYSTEM_REV_H__
-
-#include <asm/system_info.h>
-
-/*
- * board revision encoding
- * mach specific
- * the 16-31 bit are reserved for at91 generic information
- *
- * bit 31:
- *	0 => nand 8 bit
- *	1 => nand 16 bit
- */
-#define BOARD_HAVE_NAND_16BIT	(1 << 31)
-static inline int board_have_nand_16bit(void)
-{
-	return (system_rev & BOARD_HAVE_NAND_16BIT) ? 1 : 0;
-}
-
-#endif /* __ARCH_SYSTEM_REV_H__ */