sched/walt: Improve the scheduler

This change is for general scheduler improvement.

Change-Id: I17cca453e5a4e6bbf4d0b55440d9f776dc2583cb
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>

kernel/sched/walt/boost.c

@@ -192,7 +192,7 @@ static void sched_boost_disable(int type)
 	 * be disabled. Disable it first and then apply
 	 * the next boost.
 	 */
-	sb->exit();
+	sched_boosts[prev_boost].exit();
 	sched_boosts[next_boost].enter();
 }