dt-bindings: crypto: Let STM32 define Ux500 CRYP

This adds device tree bindings for the Ux500 CRYP block
as a compatible in the STM32 CRYP bindings.

The Ux500 CRYP binding has been used for ages in the kernel
device tree for Ux500 but was never documented, so fill in
the gap by making it a sibling of the STM32 CRYP block,
which is what it is.

The relationship to the existing STM32 CRYP block is pretty
obvious when looking at the register map, and I have written
patches to reuse the STM32 CRYP driver on the Ux500.

The two properties added are DMA channels and power domain.
Power domains are a generic SoC feature and the STM32 variant
also has DMA channels.

Cc: devicetree@vger.kernel.org
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>
Cc: Lionel Debieve <lionel.debieve@foss.st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>