Add device tree binding documentation for IPROC SDHCI driver.
Acked-by: NRay Jui <rjui@broadcom.com>
Signed-off-by: NCorneliu Doban <cdoban@broadcom.com>
Signed-off-by: NScott Branden <sbranden@broadcom.com>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>