clk: samsung: Enable COMPILE_TEST for Samsung clocks

Enable the COMPILE_TEST to get build coverage of some of Samsung clock
controller drivers. Still some of them will be built only if
appropriate SoC is chosen (like SOC_EXYNOS4415 or ARCH_S3C64XX).

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier@osg.samsung.com>
Tested-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Andi Shyti <andi.shyti@samsung.com>
Signed-off-by: Michael Turquette <mturquette@baylibre.com>