[PATCH] x86_64: bring back __read_mostly support to linux-2.6.17-rc2

It seems latest kernel has a wrong/missing __read_mostly implementation
for x86_64

__read_mostly macro should be declared outside of #if CONFIG_X86_VSMP block

Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>