x86_64: ACPI_CPU_FREQ must select CPU_FREQ_TABLE

Fix a compile error reported by Michel Lespinasse.
Signed-off-by: Adrian Bunk <bunk@stusta.de>

arch/x86_64/kernel/cpufreq/Kconfig

@@ -46,6 +46,7 @@ config X86_SPEEDSTEP_CENTRINO_ACPI
 
 config X86_ACPI_CPUFREQ
 	tristate "ACPI Processor P-States driver"
+	select CPU_FREQ_TABLE
 	depends on ACPI_PROCESSOR
 	help
 	  This driver adds a CPUFreq driver which utilizes the ACPI