ARM: S5P64X0: Replace the 6440 system device class definition with 64x0

The s5p64x0_sysclass should be used in place of the obselete s5p6440_sysclass.
Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Sangbeom Kim <sbkim73@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

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

@@ -79,7 +79,7 @@ extern struct sysdev_class s3c2442_sysclass;
 extern struct sysdev_class s3c2443_sysclass;
 extern struct sysdev_class s3c6410_sysclass;
 extern struct sysdev_class s3c64xx_sysclass;
-extern struct sysdev_class s5p6440_sysclass;
+extern struct sysdev_class s5p64x0_sysclass;
 extern struct sysdev_class s5p6442_sysclass;
 extern struct sysdev_class s5pv210_sysclass;