empty_zero_page is in .bss section, and it is cleared in clear_bss by
x86_64_start_kernel(). So don't clear that again in mem_init
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>