Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/kernel/sched.c b/kernel/sched.c
index f592ce6..865b433 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2309,7 +2309,7 @@
  * Cause a process which is running on another CPU to enter
  * kernel-mode, without any delay. (to get signals handled.)
  *
- * NOTE: this function doesnt have to take the runqueue lock,
+ * NOTE: this function doesn't have to take the runqueue lock,
  * because all it wants to ensure is that the remote task enters
  * the kernel. If the IPI races and the task has been migrated
  * to another CPU then no harm is done and the purpose has been
@@ -4997,7 +4997,7 @@
 	 */
 	raw_spin_lock_irqsave(&p->pi_lock, flags);
 	/*
-	 * To be able to change p->policy safely, the apropriate
+	 * To be able to change p->policy safely, the appropriate
 	 * runqueue lock must be held.
 	 */
 	rq = __task_rq_lock(p);
@@ -5705,7 +5705,7 @@
 	do_each_thread(g, p) {
 		/*
 		 * reset the NMI-timeout, listing all files on a slow
-		 * console might take alot of time:
+		 * console might take a lot of time:
 		 */
 		touch_nmi_watchdog();
 		if (!state_filter || (p->state & state_filter))