Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c
index 2f3b585..a5d0a3a 100644
--- a/kernel/time/timer_stats.c
+++ b/kernel/time/timer_stats.c
@@ -236,7 +236,7 @@
 			      unsigned int timer_flag)
 {
 	/*
-	 * It doesnt matter which lock we take:
+	 * It doesn't matter which lock we take:
 	 */
 	raw_spinlock_t *lock;
 	struct entry *entry, input;