mmc: sdhci-acpi: convert to use GPIO descriptor API

The new descriptor based GPIO interface is now the recommended and safer
way of using GPIOs from device drivers. Convert the ACPI SDHCI driver to
use that interface.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>