package/rauc: allow use of host-libp11 for crypto hardware support in host-rauc

package/rauc: allow use of host-libp11 for crypto hardware support in host-rauc

To use a private key stored on a hardware crypto module, such as an HSM
or smart card, rauc needs OpenSSL to have support for pkcs11 modules.
OpenSSL achieves this through the libp11 library.

The libp11 engine for OpenSSL is a dynamic module, so the dependency is
at rauc's runtime, rather than openssl's or rauc's build time.  However,
it still needs to be added as a dependency, so that anything that uses
host-rauc when building can be assured that host-rauc is fully
functional.

As this is a runtime dependency, there's no need for a target
dependency.  And it's only used for signing updates, which isn't done on
the target anyway.

Signed-off-by: Trent Piepho <tpiepho@impinj.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>