drivers/rtc/s3c24x0_rtc.c: fix GCC 4.6 warnings

Fix:
s3c24x0_rtc.c: In function 'rtc_get':
s3c24x0_rtc.c:67:53: warning: variable 'a_armed' set but not used
s3c24x0_rtc.c:67:45: warning: variable 'a_year' set but not used
s3c24x0_rtc.c:67:38: warning: variable 'a_mon' set but not used
s3c24x0_rtc.c:67:30: warning: variable 'a_date' set but not used
s3c24x0_rtc.c:67:22: warning: variable 'a_hour' set but not used
s3c24x0_rtc.c:67:15: warning: variable 'a_min' set but not used
s3c24x0_rtc.c:67:8: warning: variable 'a_sec' set but not used
[-Wunused-but-set-variable]

Signed-off-by: Anatolij Gustschin <agust@denx.de>
diff --git a/drivers/rtc/s3c24x0_rtc.c b/drivers/rtc/s3c24x0_rtc.c
index 9667939..c16ff2e 100644
--- a/drivers/rtc/s3c24x0_rtc.c
+++ b/drivers/rtc/s3c24x0_rtc.c
@@ -34,8 +34,7 @@
 
 #include <rtc.h>
 #include <asm/io.h>
-
-/*#define	DEBUG*/
+#include <linux/compiler.h>
 
 typedef enum {
 	RTC_ENABLE,
@@ -64,7 +63,8 @@
 {
 	struct s3c24x0_rtc *rtc = s3c24x0_get_base_rtc();
 	uchar sec, min, hour, mday, wday, mon, year;
-	uchar a_sec, a_min, a_hour, a_date, a_mon, a_year, a_armed;
+	__maybe_unused uchar a_sec, a_min, a_hour, a_date,
+			     a_mon, a_year, a_armed;
 
 	/* enable access to RTC registers */
 	SetRTC_Access(RTC_ENABLE);