package/rust-bin: host variant depends on host-cargo-bin

package/rust-bin: host variant depends on host-cargo-bin

Ensure installation of pre-built cargo binary by adding it to the
dependency list of the host variant of the pre-built Rust compiler.

Signed-off-by: Eric Le Bihan <eric.le.bihan.dev@free.fr>
Signed-off-by: Patrick Havelange <patrick.havelange@essensium.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Reviewed-by: David Pierret <david.pierret@smile.fr>
Tested-by: David Pierret <david.pierret@smile.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>