clocksource/drivers/digicolor: Add the COMPILE_TEST option

Increase the compilation test coverage by adding the COMPILE_TEST option.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
index 68a63b2..63a8c6f 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -28,7 +28,9 @@
 	bool
 
 config DIGICOLOR_TIMER
-	bool
+	bool "Digicolor timer driver" if COMPILE_TEST
+	help
+	  Enables the support for the digicolor timer driver.
 
 config DW_APB_TIMER
 	bool