cargo-c: convert to target recipe

cargo-c: convert to target recipe

This was prompted by sstatetests.SStateHashSameSigs2.test_sstate_allarch_samesigs
where adwaita-icon-theme would fail due to new librsvg introducing
cargo-c-native into dependency path.

Rather than look into why is that, I simply converted the recipe
into the standard 'target + BBCLASSEXTEND' approach.

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>