ARM: dts: exynos: Remove unused bypass-smu property from Xyref5260

The bypass-smu property is neither used nor documented in bindings.
Remove it from Xyref5260 board DTS.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>

arch/arm/boot/dts/exynos5260-xyref5260.dts

@@ -65,7 +65,6 @@
 &mmc_0 {
 	status = "okay";
 	broken-cd;
-	bypass-smu;
 	cap-mmc-highspeed;
 	supports-hs200-mode; /* 200 MHz */
 	card-detect-delay = <200>;