Reapply "Revert sched: Remove sched_setscheduler*() EXPORTs"

This commit was lost during a recent merge due to the applicable
functions changing location.  Bringing these exports sees the
out-of-tree Pixel 6 code compiling again.

This reverts commit 616d91b68c.

Some vendor modules need to set explicit priorities for kernel
threads (display, audio, graphics)

Bug: 163613349
Signed-off-by: Todd Kjos <tkjos@google.com>
Signed-off-by: Lee Jones <joneslee@google.com>
Change-Id: Ie1b119d6dd7296269d9a72cc6c891c3a8d6b91a5

kernel/sched/syscalls.c

@@ -872,6 +872,7 @@ int sched_setscheduler(struct task_struct *p, int policy,
 {
 	return _sched_setscheduler(p, policy, param, true);
 }
+EXPORT_SYMBOL_GPL(sched_setscheduler);
 
 int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
 {
@@ -902,6 +903,7 @@ int sched_setscheduler_nocheck(struct task_struct *p, int policy,
 {
 	return _sched_setscheduler(p, policy, param, false);
 }
+EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck);
 
 /*
  * SCHED_FIFO is a broken scheduler model; that is, it is fundamentally