cpufreq: ia64: remove redundant freq_table of acpi_cpufreq_data

freq_table is now stored as policy->freq_table, so drop the redundant
freq_table from struct cpufreq_acpi_io.

Signed-off-by: Pan Xinhui <xinhuix.pan@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>