Commit 8b5c2b45 disabled the internal pull-down for the strobe line
causing I/O errors in HS400 mode for various eMMC modules.

Enable the internal strobe pull-down for the ROCK 4C+ board. Also re-enable
HS400 mode, that was replaced with HS200 mode as a workaround for the
stability issues in:
2bd1d2dd ("arm64: dts: rockchip: Disable HS400 for eMMC on ROCK 4C+").

Fixes: 8b5c2b45 ("phy: rockchip: set pulldown for strobe line in dts")
Signed-off-by: Folker Schwesinger <dev@folker-schwesinger.de>
Reviewed-by: Dragan Simic <dsimic@manjaro.org>
Link: https://lore.kernel.org/r/20240327192641.14220-3-dev@folker-schwesinger.deSigned-off-by: Heiko Stuebner <heiko@sntech.de>