cpufreq: CPPC: add ACPI_PROCESSOR dependency

Without the Kconfig dependency, we can get this warning:

warning: ACPI_CPPC_CPUFREQ selects ACPI_CPPC_LIB which has unmet direct dependencies (ACPI && ACPI_PROCESSOR)

Fixes: 5477fb3bd1e8 (ACPI / CPPC: Add a CPUFreq driver for use with CPPC)
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/Kconfig.arm

@@ -268,7 +268,7 @@ config ARM_PXA2xx_CPUFREQ
 
 config ACPI_CPPC_CPUFREQ
 	tristate "CPUFreq driver based on the ACPI CPPC spec"
-	depends on ACPI
+	depends on ACPI_PROCESSOR
 	select ACPI_CPPC_LIB
 	default n
 	help