arm64: dts: meson: s400: enable sdr104 on sdio

The bcm wifi/bt device on SDIO support SDR104 and it seems to work
well following the recent mmc driver update, so enable this
ultra high speed mode

Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>