Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/drivers/scsi/mpt2sas/mpt2sas_ctl.c b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
index e92b77a..1c6d2b4 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_ctl.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_ctl.c
@@ -116,7 +116,7 @@
  * @mpi_reply: reply message frame
  * Context: none.
  *
- * Function for displaying debug info helpfull when debugging issues
+ * Function for displaying debug info helpful when debugging issues
  * in this module.
  */
 static void