uboot-phytec

sdhci: Add sdhci_deferred_probe() API

Add the sdhci_deferred_probe() function to register as the
deferred_probe() callback to the mmc core. It will in turn call the
deferred_probe() callback of the platform drivers as declared in the
sdhci_ops.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>