dt-bindings: Add bindings for Hisilicon SEC crypto accelerators.

The hip06 and hip07 SoCs contain a number of these crypto units which
accelerate AES and DES operations.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>