ARM: dts: Remove duplicate 'interrput-parent' property for exynos3250

This patch removes duplicat 'interrupt-parent' property for Exynos3250
because exynos3250.dtsi already defined 'interrupt-parent' property
as following:

In arch/arm/boot/dts/exynos3250.dtsi:

	compatible = "samsung,exynos3250";
	interrupt-parent = <&gic>;

Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>