[PATCH] x86_64 CONFIG_ACPI=n build fix

Make CONFIG_X86_PM_TIMER dependent on CONFIG_ACPI

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>