The index field of cpufreq_frequency_table has been renamed to
driver_data by commit 50701588 (cpufreq: rename index as driver_data
in cpufreq_frequency_table).

This patch updates the s3c64xx driver to match.
Signed-off-by: NCharles Keepax <ckeepax@opensource.wolfsonmicro.com>
Cc: 3.11+ <stable@vger.kernel.org> # 3.11+
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>