cam: prefer cam_sim_softc() over accessing cam_sim structure directly.

Use the accessor function to get the softc for this sim. This also drops
an unneeded cast.

Sponsored by:		Netflix
Reviewed by:		mav@, hselasky@
Differential Revision:	https://reviews.freebsd.org/D30360

sys/dev/firewire/sbp.c

@@ -2273,7 +2273,7 @@ static void
 sbp_action(struct cam_sim *sim, union ccb *ccb)
 {
 
-	struct sbp_softc *sbp = (struct sbp_softc *)sim->softc;
+	struct sbp_softc *sbp = cam_sim_softc(sim);
 	struct sbp_target *target = NULL;
 	struct sbp_dev *sdev = NULL;
 
@@ -2632,7 +2632,7 @@ sbp_poll(struct cam_sim *sim)
 	struct sbp_softc *sbp;
 	struct firewire_comm *fc;
 
-	sbp = (struct sbp_softc *)sim->softc;
+	sbp = cam_sim_softc(sim);
 	fc = sbp->fd.fc;
 
 	fc->poll(fc, 0, -1);

sys/dev/usb/storage/umass.c

@@ -2157,7 +2157,7 @@ umass_cam_detach_sim(struct umass_softc *sc)
 static void
 umass_cam_action(struct cam_sim *sim, union ccb *ccb)
 {
-	struct umass_softc *sc = (struct umass_softc *)sim->softc;
+	struct umass_softc *sc = cam_sim_softc(sim);
 
 	if (sc == NULL) {
 		ccb->ccb_h.status = CAM_SEL_TIMEOUT;
@@ -2433,7 +2433,7 @@ umass_cam_action(struct cam_sim *sim, union ccb *ccb)
 static void
 umass_cam_poll(struct cam_sim *sim)
 {
-	struct umass_softc *sc = (struct umass_softc *)sim->softc;
+	struct umass_softc *sc = cam_sim_softc(sim);
 
 	if (sc == NULL)
 		return;