mmc: sdhci: When a UHS switch fails, cycle power if regulator is used

Power needs to be removed from the card when switching to 1.8v fails.

If a regulator is used to control vmmc we need to turn the
regulator off and then back on otherwise power will not be
removed from the card.

Signed-off-by: Philip Rakity <prakity@marvell.com>
Reviewed-by: Aaron Lu <aaron.lu@amd.com>
Signed-off-by: Chris Ball <cjb@laptop.org>