clocksource/drivers/exynos_mct: Fix Kconfig and add COMPILE_TEST option

Let the platform's Kconfig to select the clock instead of having a reverse
dependency from the driver to the platform options.

Add the COMPILE_TEST option for the compilation test coverage. Due to the
non portable 'delay' code, this driver is only compilable on ARM.
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

arch/arm/mach-exynos/Kconfig

@@ -27,6 +27,7 @@ menuconfig ARCH_EXYNOS
 	select SRAM
 	select THERMAL
 	select MFD_SYSCON
+	select CLKSRC_EXYNOS_MCT
 	help
 	  Support for SAMSUNG EXYNOS SoCs (EXYNOS4/5)
 

drivers/clocksource/Kconfig

@@ -231,8 +231,8 @@ config CLKSRC_METAG_GENERIC
 	  This option enables support for the Meta per-thread timers.
 
 config CLKSRC_EXYNOS_MCT
-	def_bool y if ARCH_EXYNOS
-	depends on !ARM64
+	bool "Exynos multi core timer driver" if COMPILE_TEST
+	depends on ARM
 	help
 	  Support for Multi Core Timer controller on Exynos SoCs.