linux-imx

Documentation: dt: kona-sdhci: Add clocks property

The Kona SDHCI block requires a clock that must be specified in the
device tree.  Update the documentation to reflect this requirement.

Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Signed-off-by: Christian Daudt <bcm@fixthebug.org>