ARM: EXYNOS4: Add clkdev support

Signed-off-by: NThomas Abraham <thomas.ab@samsung.com>
[kgene.kim@samsung.com: removed changes of mach-exynos4/time.c]
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

arch/arm/Kconfig

@@ -772,6 +772,7 @@ config ARCH_EXYNOS4
 	select ARCH_SPARSEMEM_ENABLE
 	select GENERIC_GPIO
 	select HAVE_CLK
+	select CLKDEV_LOOKUP
 	select ARCH_HAS_CPUFREQ
 	select GENERIC_CLOCKEVENTS
 	select HAVE_S3C_RTC if RTC_CLASS