tty:serial:mvebu-uart:fix a wrong return

commit 4a3e208474204e879d22a310b244cb2f39e5b1f8 upstream.

in this place, the function should return a
negative value and the PTR_ERR already returns
a negative,so return -PTR_ERR() is wrong.

Signed-off-by: tangbin <tangbin@cmss.chinamobile.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200305013823.20976-1-tangbin@cmss.chinamobile.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c
index 401c983..a10e4aa 100644
--- a/drivers/tty/serial/mvebu-uart.c
+++ b/drivers/tty/serial/mvebu-uart.c
@@ -581,7 +581,7 @@
 
 	port->membase = devm_ioremap_resource(&pdev->dev, reg);
 	if (IS_ERR(port->membase))
-		return -PTR_ERR(port->membase);
+		return PTR_ERR(port->membase);
 
 	data = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_uart_data),
 			    GFP_KERNEL);