enable large bzImages on x86_64. (fix is from x86's build.c) Using this
patch i have successfully built and booted an allyesconfig 13MB+ bzImage
on x86_64 too:

 $ size64 vmlinux
    text    data     bss     dec     hex filename
 23444831        8202642 3439360 35086833        21761f1 vmlinux

 -rw-rw-r--  1 mingo mingo 13121740 Apr 19 09:32 arch/x86_64/boot/bzImage
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>