cmd: return code when tlv_eeprom incorrectly called

A command called with incorrect parameters should set $? to 1 (false).
Instead of calling cmd_usage(cmdtp) and then returning 0 just return
CMD_RET_FAILURE.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Acked-by: Baruch Siach <baruch@tkos.co.il>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/cmd/tlv_eeprom.c b/cmd/tlv_eeprom.c
index bf8d453..4591ff3 100644
--- a/cmd/tlv_eeprom.c
+++ b/cmd/tlv_eeprom.c
@@ -479,17 +479,14 @@
 			show_tlv_devices();
 			break;
 		default:
-			cmd_usage(cmdtp);
-			break;
+			return CMD_RET_USAGE;
 		}
 		return 0;
 	}
 
 	// The set command takes one or two args.
-	if (argc > 4) {
-		cmd_usage(cmdtp);
-		return 0;
-	}
+	if (argc > 4)
+		return CMD_RET_USAGE;
 
 	// Set command. If the TLV exists in the EEPROM, delete it. Then if
 	// data was supplied for this TLV add the TLV with the new contents at
@@ -512,7 +509,7 @@
 		current_dev = devnum;
 		has_been_read = 0;
 	} else {
-		cmd_usage(cmdtp);
+		return CMD_RET_USAGE;
 	}
 
 	return 0;