cpufreq: s3c64xx: Rename index to driver_data

cpufreq: s3c64xx: Rename index to driver_data

commit 0e8244322b7fc45fd11a1c45f70b6bacddf4986f upstream.

The index field of cpufreq_frequency_table has been renamed to
driver_data by commit 5070158 (cpufreq: rename index as driver_data
in cpufreq_frequency_table).

This patch updates the s3c64xx driver to match.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>