sched: Simplify sched_lend_user_prio_cond()

If 'td_lend_user_pri' has the expected value, there is no need to check
the fields that sched_lend_user_prio() modifies, they either are already
good or soon will be ('td->td_lend_user_pri' has just been changed by
a concurrent update).

Reviewed by:            kib
Approved by:            emaste (mentor)
MFC after:              2 weeks
Sponsored by:           The FreeBSD Foundation
Differential Revision:  https://reviews.freebsd.org/D44050

sys/kern/sched_4bsd.c

@@ -981,15 +981,9 @@ void
 sched_lend_user_prio_cond(struct thread *td, u_char prio)
 {
 
-	if (td->td_lend_user_pri != prio)
-		goto lend;
-	if (td->td_user_pri != min(prio, td->td_base_user_pri))
-		goto lend;
-	if (td->td_priority != td->td_user_pri)
-		goto lend;
-	return;
+	if (td->td_lend_user_pri == prio)
+		return;
 
-lend:
 	thread_lock(td);
 	sched_lend_user_prio(td, prio);
 	thread_unlock(td);

sys/kern/sched_ule.c

@@ -2007,15 +2007,9 @@ void
 sched_lend_user_prio_cond(struct thread *td, u_char prio)
 {
 
-	if (td->td_lend_user_pri != prio)
-		goto lend;
-	if (td->td_user_pri != min(prio, td->td_base_user_pri))
-		goto lend;
-	if (td->td_priority != td->td_user_pri)
-		goto lend;
-	return;
+	if (td->td_lend_user_pri == prio)
+		return;
 
-lend:
 	thread_lock(td);
 	sched_lend_user_prio(td, prio);
 	thread_unlock(td);