USB: ch341: replace printk warnings with dev_err

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 59eff72..5e455f4 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -399,8 +399,8 @@
 	r = ch341_control_in(port->serial->dev, CH341_REQ_READ_REG,
 			ch341_break_reg, 0, break_reg, sizeof(break_reg));
 	if (r < 0) {
-		printk(KERN_WARNING "%s: USB control read error whilst getting"
-				" break register contents.\n", __FILE__);
+		dev_err(&port->dev, "%s - USB control read error (%d)\n",
+				__func__, r);
 		return;
 	}
 	dbg("%s - initial ch341 break register contents - reg1: %x, reg2: %x",
@@ -420,8 +420,8 @@
 	r = ch341_control_out(port->serial->dev, CH341_REQ_WRITE_REG,
 			ch341_break_reg, reg_contents);
 	if (r < 0)
-		printk(KERN_WARNING "%s: USB control write error whilst setting"
-				" break register contents.\n", __FILE__);
+		dev_err(&port->dev, "%s - USB control write error (%d)\n",
+				__func__, r);
 }
 
 static int ch341_tiocmset(struct tty_struct *tty, struct file *file,