[CPUFREQ] Longhaul - Remove "ignore_latency" option

There is no need to have this option in Longhaul anymore.
It was for laptop with CLE266 chipset in times, when only
ACPI C3 was used to switch frequency. Now we have native
support not only for CLE266, but CN400 too. Would be good
to have support for PN266, but I can't find datasheet for it.
Looks like BIOS for CPU's faster then 1GHz don't support
ACPI C2 nor C3.

Signed-off-by: Rafa³ Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>