clocksource/drivers/pxa_timer: 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 d4221e0..e07ada9 100644
--- a/drivers/clocksource/Kconfig
+++ b/drivers/clocksource/Kconfig
@@ -307,7 +307,9 @@
 	select CLKSRC_OF
 
 config CLKSRC_PXA
-	bool
+	bool "Clocksource for PXA or SA-11x0 platform" if COMPILE_TEST
+	depends on GENERIC_CLOCKEVENTS
+	select CLKSRC_MMIO
 	help
 	  This enables OST0 support available on PXA and SA-11x0
 	  platforms.