clocksource/drivers/bcm_kona: Add the COMPILE_TEST option

Change the Kconfig option logic to fullfil with the current approach.

A new Kconfig option is added, CONFIG_BCM_KONA_TIMER and is selected by the
platform. Then the clocksource's Kconfig is changed to make this option
selectable by the user if the COMPILE_TEST option is set. Otherwise, it is
up to the platform's Kconfig to select the timer.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 01ecd88..a3cccf5 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -34,6 +34,13 @@
 	help
 	  Enables the support for the BCM2835 timer driver.
 
+config BCM_KONA_TIMER
+	bool "BCM mobile timer driver" if COMPILE_TEST
+	depends on GENERIC_CLOCKEVENTS
+	select CLKSRC_MMIO
+	help
+	  Enables the support for the BCM Kona mobile timer driver.
+
 config DIGICOLOR_TIMER
 	bool "Digicolor timer driver" if COMPILE_TEST
 	depends on GENERIC_CLOCKEVENTS