mmc: sdhci-pxav2: add optional pinctrl for SDIO IRQ workaround

The PXA168 errata recommends that the CMD signal should be detached from
the SD bus while performing the dummy CMD0 to restart the clock.
Implement this using pinctrl states.

Signed-off-by: Doug Brown <doug@schmorgal.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20230116194401.20372-8-doug@schmorgal.com


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