ARM: S5P64X0: Fix SPI platform device name

Changed the SPI platform device name from S5P6450 to S5P64x0 as it is
defined common for both S5p6440 and S5P6450 in dev-spi.c of S5P64x0.

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

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

@@ -75,10 +75,8 @@ extern struct platform_device s5pc100_device_spi1;
 extern struct platform_device s5pc100_device_spi2;
 extern struct platform_device s5pv210_device_spi0;
 extern struct platform_device s5pv210_device_spi1;
-extern struct platform_device s5p6440_device_spi0;
-extern struct platform_device s5p6440_device_spi1;
-extern struct platform_device s5p6450_device_spi0;
-extern struct platform_device s5p6450_device_spi1;
+extern struct platform_device s5p64x0_device_spi0;
+extern struct platform_device s5p64x0_device_spi1;
 
 extern struct platform_device s3c_device_hwmon;