Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index 987e9bf..d9906eb 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -35,7 +35,7 @@
  *
  *  Lonnie Mendez <dignome@gmail.com>
  *  04-10-2004
- *	Driver modified to support dynamic line settings.  Various improvments
+ *	Driver modified to support dynamic line settings.  Various improvements
  *      and features.
  *
  *  Neil Whelchel