U-Boot has terrible support for SPL stage regulators setup needed for
sdmmc0 to work on Quartz64-A. We avoid all the regulator setup dance
by using pwren pinmux on sdmmc0 in U-Boot and we achieve the needed
polarity for the enable pin (active low) via a new
CONFIG_MMC_DW_PWREN_POLARITY config property.
Signed-off-by: Ondrej Jirman <megi@xff.cz>
81b1b97476