ARM: dts: Add cap-sdio-irq to wifi mmc node for exynos5250-snow

Enabling SDIO IRQ signalling for the wifi MMC/SDIO slot
doubles the transmission transfer rate.
Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Kukjin Kim <kgene@kernel.org>

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

@@ -539,6 +539,7 @@ &mmc_3 {
 	status = "okay";
 	num-slots = <1>;
 	broken-cd;
+	cap-sdio-irq;
 	card-detect-delay = <200>;
 	samsung,dw-mshc-ciu-div = <3>;
 	samsung,dw-mshc-sdr-timing = <2 3>;