ARM: exynos_defconfig: Enable bus frequency scaling with devfreq

This patch enables the bus frequency scaling driver with devfreq and
devfreq-event framework.  Devfreq is already supported on Odroid U3/XU3,
Trats2 and Rinato/Monk boards.
Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
[k.kozlowski: Don't enable symbols already selected, adjust commit msg]
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

arch/arm/configs/exynos_defconfig

@@ -219,6 +219,12 @@ CONFIG_CROS_EC_CHARDEV=y
 CONFIG_COMMON_CLK_MAX77686=y
 CONFIG_COMMON_CLK_MAX77802=y
 CONFIG_COMMON_CLK_S2MPS11=y
+CONFIG_PM_DEVFREQ=y
+CONFIG_DEVFREQ_GOV_PERFORMANCE=y
+CONFIG_DEVFREQ_GOV_POWERSAVE=y
+CONFIG_DEVFREQ_GOV_USERSPACE=y
+CONFIG_ARM_EXYNOS_BUS_DEVFREQ=y
+CONFIG_DEVFREQ_EVENT_EXYNOS_NOCP=y
 CONFIG_EXTCON=y
 CONFIG_EXTCON_MAX14577=y
 CONFIG_EXTCON_MAX77693=y