dt-bindings: sdhci-of-at91: new compatible string and update properties

There is a new compatible string for the SAM9X60 sdhci device. It involves
an update of the properties about the clocks stuff.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20191128074522.69706-1-ludovic.desroches@microchip.com


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