cpufreq / e_powersaver: Fix linker error when ACPI processor is a module

on i386:
CONFIG_ACPI_PROCESSOR=m
CONFIG_X86_E_POWERSAVER=y

drivers/built-in.o: In function `eps_cpu_init.part.8':
e_powersaver.c:(.text.unlikely+0x2243): undefined reference to `acpi_processor_register_performance'
e_powersaver.c:(.text.unlikely+0x22a2): undefined reference to `acpi_processor_unregister_performance'
e_powersaver.c:(.text.unlikely+0x246b): undefined reference to `acpi_processor_get_bios_limit'

X86_E_POWERSAVER should also depend on ACPI_PROCESSOR.
Signed-off-by: NRafal Bilski <rafalbilski@interia.pl>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/Kconfig.x86

@@ -272,7 +272,7 @@ config X86_LONGHAUL
 config X86_E_POWERSAVER
 	tristate "VIA C7 Enhanced PowerSaver (DANGEROUS)"
 	select CPU_FREQ_TABLE
-	depends on X86_32
+	depends on X86_32 && ACPI_PROCESSOR
 	help
 	  This adds the CPUFreq driver for VIA C7 processors.  However, this driver
 	  does not have any safeguards to prevent operating the CPU out of spec