x86: Remove left over system_64.h

Left-over from the x86 merge ...
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4D3E23D1.7010405@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/system_64.h

-#ifndef _ASM_X86_SYSTEM_64_H
-#define _ASM_X86_SYSTEM_64_H
-
-#include <asm/segment.h>
-#include <asm/cmpxchg.h>
-
-
-static inline unsigned long read_cr8(void)
-{
-	unsigned long cr8;
-	asm volatile("movq %%cr8,%0" : "=r" (cr8));
-	return cr8;
-}
-
-static inline void write_cr8(unsigned long val)
-{
-	asm volatile("movq %0,%%cr8" :: "r" (val) : "memory");
-}
-
-#include <linux/irqflags.h>
-
-#endif /* _ASM_X86_SYSTEM_64_H */