Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
index 0948f10..c7fc7fd 100644
--- a/mm/hwpoison-inject.c
+++ b/mm/hwpoison-inject.c
@@ -1,4 +1,4 @@
-/* Inject a hwpoison memory failure on a arbitary pfn */
+/* Inject a hwpoison memory failure on a arbitrary pfn */
 #include <linux/module.h>
 #include <linux/debugfs.h>
 #include <linux/kernel.h>