cpufreq: cpufreq-cpu0: fix CPU_THERMAL dependency

5fbfbcd ("cpufreq: cpufreq-cpu0: remove dependency on THERMAL and
REGULATOR") was a little too quick in completely removing the dependency
on the THERMAL driver.

The problem is that while there are inline wrappers to turn the thermal
API calls into empty functions, those do not help if the cpu-thermal
driver is a loadable module and cpufreq-cpu0 is builtin.

Since CONFIG_CPU_THERMAL is a bool option that decides whether the cpu
code is built into the thermal module or not, we have to use a dependency
on the thermal driver itself. However, if CPU_THERMAL is disabled, we
don't need the dependency, hence the strange '!CPU_THERMAL || THERMAL'
construct.

Fixes: 5fbfbcd ("cpufreq: cpufreq-cpu0: remove dependency on THERMAL and REGULATOR")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/cpufreq/Kconfig

@@ -186,6 +186,8 @@ config CPU_FREQ_GOV_CONSERVATIVE
 config GENERIC_CPUFREQ_CPU0
 	tristate "Generic CPU0 cpufreq driver"
 	depends on HAVE_CLK && OF
+	# if CPU_THERMAL is on and THERMAL=m, CPU0 cannot be =y:
+	depends on !CPU_THERMAL || THERMAL
 	select PM_OPP
 	help
 	  This adds a generic cpufreq driver for CPU0 frequency management.