PM / devfreq: exynos5: Add CONFIG_PM_OPP dependency to fix probe fail

This patch add CONFIG_PM_OPP dependecy to exynos5_bus driver
to fix probe fail. If CONFIG_PM_OPP is disabled, dev_pm_opp_find_freq_floor()
will always return ERR_PTR(-EINVAL) error.
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>

drivers/devfreq/Kconfig

@@ -84,6 +84,7 @@ config ARM_EXYNOS5_BUS_DEVFREQ
 	depends on SOC_EXYNOS5250
 	select ARCH_HAS_OPP
 	select DEVFREQ_GOV_SIMPLE_ONDEMAND
+	select PM_OPP
 	help
 	  This adds the DEVFREQ driver for Exynos5250 bus interface (vdd_int).
 	  It reads PPMU counters of memory controllers and adjusts the