ARM: EXYNOS: Fix incorrect help text

Changed Exynos4 -> EXYNOS5.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-exynos/Kconfig

@@ -418,8 +418,8 @@ config MACH_EXYNOS5_DT
 	select USE_OF
 	select ARM_AMBA
 	help
-	  Machine support for Samsung Exynos4 machine with device tree enabled.
-	  Select this if a fdt blob is available for the EXYNOS4 SoC based board.
+	  Machine support for Samsung EXYNOS5 machine with device tree enabled.
+	  Select this if a fdt blob is available for the EXYNOS5 SoC based board.
 
 if ARCH_EXYNOS4