Fix common misspellings

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
diff --git a/drivers/net/can/softing/softing_main.c b/drivers/net/can/softing/softing_main.c
index aeea9f9..7a70709 100644
--- a/drivers/net/can/softing/softing_main.c
+++ b/drivers/net/can/softing/softing_main.c
@@ -218,7 +218,7 @@
 	ptr = buf;
 	cmd = *ptr++;
 	if (cmd == 0xff)
-		/* not quite usefull, probably the card has got out */
+		/* not quite useful, probably the card has got out */
 		return 0;
 	netdev = card->net[0];
 	if (cmd & CMD_BUS2)