ARM: dts: rockchip: Make rk3288-veyron-minnie run at hs200

As some point hs200 was failing on rk3288-veyron-minnie.  See commit
98492678 ("ARM: dts: rockchip: temporarily remove emmc hs200 speed
from rk3288 minnie").  Although I didn't track down exactly when it
started working, it seems to work OK now, so let's turn it back on.

To test this, I booted from SD card and then used this script to
stress the enumeration process after fixing a memory leak [1]:
  cd /sys/bus/platform/drivers/dwmmc_rockchip
  for i in $(seq 1 3000); do
    echo "========================" $i
    echo ff0f0000.dwmmc > unbind
    sleep .5
    echo ff0f0000.dwmmc > bind
    while true; do
      if [ -e /dev/mmcblk2 ]; then
        break;
      fi
      sleep .1
    done
  done

It worked fine.

[1] https://lkml.kernel.org/r/20190503233526.226272-1-dianders@chromium.orgSigned-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm/boot/dts/rk3288-veyron-minnie.dts

@@ -90,10 +90,6 @@ &backlight {
 	pwm-off-delay-ms = <200>;
 };
 
-&emmc {
-	/delete-property/mmc-hs200-1_8v;
-};
-
 &gpio_keys {
 	pinctrl-0 = <&pwr_key_l &ap_lid_int_l &volum_down_l &volum_up_l>;