serial: tegra: Only print FIFO error message when an error occurs

The Tegra serial driver always prints an error message when enabling the
FIFO for devices that have support for checking the FIFO enable status.
Fix this by displaying the error message, only when an error occurs.

Finally, update the error message to make it clear that enabling the
FIFO failed and display the error code.

Fixes: 222dcdff ("serial: tegra: check for FIFO mode enabled status")
Cc: <stable@vger.kernel.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/20210630125643.264264-1-jonathanh@nvidia.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial-tegra.c

@@ -1045,9 +1045,11 @@ static int tegra_uart_hw_init(struct tegra_uart_port *tup)
 
 	if (tup->cdata->fifo_mode_enable_status) {
 		ret = tegra_uart_wait_fifo_mode_enabled(tup);
-		dev_err(tup->uport.dev, "FIFO mode not enabled\n");
-		if (ret < 0)
+		if (ret < 0) {
+			dev_err(tup->uport.dev,
+				"Failed to enable FIFO mode: %d\n", ret);
 			return ret;
+		}
 	} else {
 		/*
 		 * For all tegra devices (up to t210), there is a hardware