arm64: dts: allwinner: Pine H64: Enable HS200 eMMC mode

The eMMC modules offered for the Pine64 boards are capable of the HS200
eMMC speed mode, when observing the frequency limit of 150 MHz.

Enable that in the DT.

This increases the interface speed from ~80 MB/s to ~120 MB/s.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210113152630.28810-9-andre.przywara@arm.com