ARM: dts: Fix the RTC DT node name for Exynos5250

Fixes the RTC DT node name for Exynos5250 as per the DT node naming
convention.

Signed-off-by: Vikas Sajjan <vikas.sajjan@linaro.org>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/boot/dts/exynos5250-snow.dts

@@ -171,7 +171,7 @@
 		};
 	};
 
-	rtc {
+	rtc@101E0000 {
 		status = "okay";
 	};