Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>

mm/kmemleak.c

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 84225f3..c1d58675 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -265,7 +265,7 @@
 } while (0)
 
 /*
- * Macro invoked when a serious kmemleak condition occured and cannot be
+ * Macro invoked when a serious kmemleak condition occurred and cannot be
  * recovered from. Kmemleak will be disabled and further allocation/freeing
  * tracing no longer available.
  */
@@ -1006,7 +1006,7 @@
 
 /*
  * Memory scanning is a long process and it needs to be interruptable. This
- * function checks whether such interrupt condition occured.
+ * function checks whether such interrupt condition occurred.
  */
 static int scan_should_stop(void)
 {
@@ -1733,7 +1733,7 @@
 
 	if (atomic_read(&kmemleak_error)) {
 		/*
-		 * Some error occured and kmemleak was disabled. There is a
+		 * Some error occurred and kmemleak was disabled. There is a
 		 * small chance that kmemleak_disable() was called immediately
 		 * after setting kmemleak_initialized and we may end up with
 		 * two clean-up threads but serialized by scan_mutex.