[ARM] S3C64XX: Add s3c6410_sysclass export

Add definition for s3c6410_sysclass which was missing
from arch/arm/plat-s3c/include/plat/cpu.h.
Signed-off-by: NBen Dooks <ben-linux@fluff.org>

arch/arm/plat-s3c/include/plat/cpu.h

@@ -69,3 +69,4 @@ extern struct sysdev_class s3c2412_sysclass;
 extern struct sysdev_class s3c2440_sysclass;
 extern struct sysdev_class s3c2442_sysclass;
 extern struct sysdev_class s3c2443_sysclass;
+extern struct sysdev_class s3c6410_sysclass;