PM / OPP: fix condition for empty of_init_opp_table()

randconfig build reports the following error which is caused by
CONFIG_PM_OPP being unset.

  CC      arch/arm/mach-imx/mach-imx6q.o
arch/arm/mach-imx/mach-imx6q.c: In function ‘imx6q_opp_init’:
arch/arm/mach-imx/mach-imx6q.c:248:2: error: implicit declaration of function ‘of_init_opp_table’ [-Werror=implicit-function-declaration]

Fix the error by giving a more correct condition for empty
of_init_opp_table() implementation.
Reported-by: Rob Herring <robherring2@gmail.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

include/linux/opp.h

@@ -47,15 +47,6 @@ int opp_enable(struct device *dev, unsigned long freq);
 int opp_disable(struct device *dev, unsigned long freq);
 
 struct srcu_notifier_head *opp_get_notifier(struct device *dev);
-
-#ifdef CONFIG_OF
-int of_init_opp_table(struct device *dev);
-#else
-static inline int of_init_opp_table(struct device *dev)
-{
-	return -EINVAL;
-}
-#endif /* CONFIG_OF */
 #else
 static inline unsigned long opp_get_voltage(struct opp *opp)
 {
@@ -112,6 +103,15 @@ static inline struct srcu_notifier_head *opp_get_notifier(struct device *dev)
 }
 #endif		/* CONFIG_PM_OPP */
 
+#if defined(CONFIG_PM_OPP) && defined(CONFIG_OF)
+int of_init_opp_table(struct device *dev);
+#else
+static inline int of_init_opp_table(struct device *dev)
+{
+	return -EINVAL;
+}
+#endif
+
 #if defined(CONFIG_CPU_FREQ) && defined(CONFIG_PM_OPP)
 int opp_init_cpufreq_table(struct device *dev,
 			    struct cpufreq_frequency_table **table);