USB: serial: Remove unnecessary \n's from dbg uses

#define dbg adds the newline, messages shouldn't.
Converted dbg("%s", "some string") to dbg("some string")

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index d59262e..1c84355 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -1836,7 +1836,7 @@
 	spin_lock_irqsave(&priv->tx_lock, flags);
 	if (priv->tx_outstanding_urbs > URB_UPPER_LIMIT) {
 		spin_unlock_irqrestore(&priv->tx_lock, flags);
-		dbg("%s - write limit hit\n", __func__);
+		dbg("%s - write limit hit", __func__);
 		return 0;
 	}
 	priv->tx_outstanding_urbs++;