ahc_unbusy_tcl
ahc_unbusy_tcl(ahc, BUILD_TCL(i << 4, 0));
ahc_unbusy_tcl(ahc, BUILD_TCL(i << 4, lun));
ahc_unbusy_tcl(ahc, BUILD_TCL(i << 4, j));
void ahc_unbusy_tcl(struct ahc_softc *, u_int);