Currently only the ondemand and performance CPUFreq policy governors are
enabled in the Exynos defconfig. But the other governors are also useful
for some cases, enable them to allow users change the default if needed.

The options are enabled as module to keep the kernel image size minimal.
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>