staging: comedi: remove break after return

Remove "break" statement after a "return" statement as
it does not get executed.

Deadcode found by coccinelle --debug option
Signed-off-by: NSupriya Karanth <iskaranth@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/comedi/drivers/ni_mio_common.c

@@ -3811,8 +3811,6 @@ static int ni_serial_insn_config(struct comedi_device *dev,
 			      Clock_and_FOUT_Register);
 		return 1;
 
-		break;
-
 	case INSN_CONFIG_BIDIRECTIONAL_DATA:
 
 		if (devpriv->serial_interval_ns == 0)