Allow psi monitor users to setched kernel threads

psi monitor sched_setscheduler(kworker->task, SCHED_FIFO, &param) was added into pa/1282597

Bug: 131252752
Bug: 129476847
Test: build
Change-Id: I69fdd90e4a39da8d33b417efc7ea7a0da9d9290b
diff --git a/private/system_server.te b/private/system_server.te
index 14c6dd6..cf9bf23 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -123,6 +123,9 @@
 allow system_server mediaserver:process { getsched setsched };
 allow system_server bootanim:process { getsched setsched };
 
+# Set scheduling info for psi monitor thread.
+allow system_server kernel:process { getsched setsched };
+
 # Allow system_server to write to /proc/<pid>/*
 allow system_server domain:file w_file_perms;