Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/drivers/staging/vt6656/rxtx.c b/drivers/staging/vt6656/rxtx.c
index 8f18578..5185d61 100644
--- a/drivers/staging/vt6656/rxtx.c
+++ b/drivers/staging/vt6656/rxtx.c
@@ -1938,7 +1938,7 @@
  *  Out:
  *      none
  *
- * Return Value: CMD_STATUS_PENDING if MAC Tx resource avaliable; otherwise FALSE
+ * Return Value: CMD_STATUS_PENDING if MAC Tx resource available; otherwise FALSE
  *
 -*/