Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/mm/ksm.c b/mm/ksm.c
index 1bbe785..942dfc7 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -720,7 +720,7 @@
 		swapped = PageSwapCache(page);
 		flush_cache_page(vma, addr, page_to_pfn(page));
 		/*
-		 * Ok this is tricky, when get_user_pages_fast() run it doesnt
+		 * Ok this is tricky, when get_user_pages_fast() run it doesn't
 		 * take any lock, therefore the check that we are going to make
 		 * with the pagecount against the mapcount is racey and
 		 * O_DIRECT can happen right after the check.