Enable cesa driver to work with Linux DT binding

Linux device tree binding, whose usage is obligatory,
comprises faulty representation of Marvell cryptographic
engine (CESA) - two engines are artificially gathered into
single DT node, in order to avoid certain SW limitation.

This patch improves the cesa driver to support above binding,
depending on compatible string, which helps to ensure
backward compatibility.

Submitted by: Patryk Duda
Obtained from: Semihalf
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D14760