mmc: sdhci: Introduce sdhci_set_power_and_bus_voltage()

Some controllers diverge from the standard way of setting power and need
their bus voltage register to be configured regardless of the whether
they use regulators. As this is a common pattern across sdhci hosts,
create a helper function.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200306174413.20634-2-nsaenzjulienne@suse.de


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>