dt-bindings: crypto: Convert ti,omap2-aes to DT schema

Convert the TI OMAP AES binding to DT schema format. It's a straight
forward conversion.

Make "ti,hwmods" not required as it is deprecated and only used on
OMAP2.

Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>