mmc: sdhci: move remaining power handling into sdhci_set_power()

Move the remaining parts of the power handling in sdhci_do_set_ios()
into sdhci_set_power().

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Tested-by: Markus Pargmann <mpa@pengutronix.de>
Tested-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>