arm64: dts: meson: misc fixups for w400 dtsi

Current devices using the W400 dtsi show mmc tuning errors:

[12483.917391] mmc0: tuning execution failed: -5
[30535.551221] mmc0: tuning execution failed: -5
[35359.953671] mmc0: tuning execution failed: -5
[35561.875332] mmc0: tuning execution failed: -5
[61733.348709] mmc0: tuning execution failed: -5

Removing "sd-uhs-sdr50" from the SDIO node prevents this. We also add
keep-power-in-suspend to the SDIO node and fix an indentation.

Fixes: 3cb74db9

 ("arm64: dts: meson: convert ugoos-am6 to common w400 dtsi")
Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Link: https://lore.kernel.org/r/20200721013952.11635-1-christianshewitt@gmail.com