PM / devfreq: Move exynos4 devfreq driver into a new sub-directory

In anticipation of the new exynos5 devfreq and ppmu driver, create
an exynos sub-directory. Move the existing exynos4 devfreq driver
into the same.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Acked-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Cc: Jonghwan Choi <jhbird.choi@samsung.com>
Cc: Kukjin Kim <kgene.kim@samsung.com>

drivers/devfreq/Makefile

@@ -5,4 +5,4 @@ obj-$(CONFIG_DEVFREQ_GOV_POWERSAVE)	+= governor_powersave.o
 obj-$(CONFIG_DEVFREQ_GOV_USERSPACE)	+= governor_userspace.o
 
 # DEVFREQ Drivers
-obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos4_bus.o
+obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos/

drivers/devfreq/exynos/Makefile

+# Exynos DEVFREQ Drivers
+obj-$(CONFIG_ARM_EXYNOS4_BUS_DEVFREQ)	+= exynos4_bus.o