fuspi: silence build warning, plug resource leak

This silences an "unused label" warning as well as fixes the attach fail
path that wasn't releasing resources.

Submitted by:   Nicholas O'Brien <nickisobrien_gmail.com>
Sponsored by:	Axiado
Differential Revision: https://reviews.freebsd.org/D24004

sys/riscv/sifive/fu540_spi.c

@@ -348,10 +348,8 @@ fuspi_attach(device_t dev)
 
 	return (0);
 
-fail1:
-	bus_release_resources(dev, fuspi_spec, &sc->res);
-
 fail:
+	bus_release_resources(dev, fuspi_spec, &sc->res);
 	mtx_destroy(&sc->mtx);
 	return (error);
 }