clocksource: convert 32-bit down counting clocksource on S5PV210/S5P64X0

Convert the S5PV210/S5P64X0 32-bit down-counting clocksource to
the generic mmio clocksource infrastructure

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 2b5f82f..d39f532 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -726,6 +726,7 @@
 	select GENERIC_GPIO
 	select HAVE_CLK
 	select CLKDEV_LOOKUP
+	select CLKSRC_MMIO
 	select HAVE_S3C2410_WATCHDOG if WATCHDOG
 	select GENERIC_CLOCKEVENTS
 	select HAVE_SCHED_CLOCK
@@ -756,6 +757,7 @@
 	select GENERIC_GPIO
 	select HAVE_CLK
 	select CLKDEV_LOOKUP
+	select CLKSRC_MMIO
 	select ARM_L1_CACHE_SHIFT_6
 	select ARCH_HAS_CPUFREQ
 	select GENERIC_CLOCKEVENTS