ARM: SAMSUNG: fix to prevent declaring duplicated

The plat/clock.h revised to prevent declaring duplicated.

Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
diff --git a/arch/arm/plat-samsung/include/plat/clock.h b/arch/arm/plat-samsung/include/plat/clock.h
index 8f95700..73c66d4 100644
--- a/arch/arm/plat-samsung/include/plat/clock.h
+++ b/arch/arm/plat-samsung/include/plat/clock.h
@@ -9,6 +9,9 @@
  * published by the Free Software Foundation.
 */
 
+#ifndef __ASM_PLAT_CLOCK_H
+#define __ASM_PLAT_CLOCK_H __FILE__
+
 #include <linux/spinlock.h>
 #include <linux/clkdev.h>
 
@@ -124,3 +127,5 @@
 /* Global watchdog clock used by arch_wtd_reset() callback */
 
 extern struct clk *s3c2410_wdtclk;
+
+#endif /* __ASM_PLAT_CLOCK_H */