ARM: S3C64XX: Separate out regulator and frequency latencies

Currently the transition latency reported by the S3C64xx cpufreq
driver includes both the time for the CPU to reclock itself and
the time for a regulator to change voltage. This means that if
a regulator is not in use then the transition latency reported
is excessively high.

In future the regulator API will be extended to report latencies
so the driver will be able to query the performance of a given
regulator.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>