Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 7f74019..4673bc0 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -101,7 +101,7 @@
 		 * to the work-to-be schedule is freed.
 		 *
 		 * Thus we need to keep the io structure still valid here after
-		 * convertion finished. The io structure has a flag to
+		 * conversion finished. The io structure has a flag to
 		 * avoid double converting from both fsync and background work
 		 * queue work.
 		 */