ARM: EXYNOS: Remove build warning without enabling PM

Fixed following build warning with exynos4_defconfig.
arch/arm/mach-exynos/clock.c:33: warning: 'exynos4_clock_save' defined but not used
arch/arm/mach-exynos/clock-exynos4210.c:35: warning: 'exynos4210_clock_save' defined but not used
arch/arm/mach-exynos/clock-exynos4212.c:35: warning: 'exynos4212_clock_save' defined but not used

Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
diff --git a/arch/arm/mach-exynos/clock.c b/arch/arm/mach-exynos/clock.c
index 5a8c42e..187287a 100644
--- a/arch/arm/mach-exynos/clock.c
+++ b/arch/arm/mach-exynos/clock.c
@@ -30,6 +30,7 @@
 
 #include "common.h"
 
+#ifdef CONFIG_PM_SLEEP
 static struct sleep_save exynos4_clock_save[] = {
 	SAVE_ITEM(S5P_CLKDIV_LEFTBUS),
 	SAVE_ITEM(S5P_CLKGATE_IP_LEFTBUS),
@@ -93,6 +94,7 @@
 	SAVE_ITEM(S5P_CLKGATE_SCLKCPU),
 	SAVE_ITEM(S5P_CLKGATE_IP_CPU),
 };
+#endif
 
 struct clk clk_sclk_hdmi27m = {
 	.name		= "sclk_hdmi27m",