dt-bindings: crypto: Convert Atmel SHA to yaml

Convert Atmel SHA documentation to yaml format. With the conversion the
clock and clock-names properties are made mandatory. The driver returns
-EINVAL if "sha_clk" is not found, reflect that in the bindings and make
the clock and clock-names properties mandatory. Update the example to
better describe how one should define the dt node.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220211093922.456634-4-tudor.ambarus@microchip.com