USB: serial: ftdi_sio: clean up printk format specifier

The latency is an unsigned int and should be printed as such (even if it
only holds values in the range 0..255).

Signed-off-by: Daniels Umanovskis <du@axentia.se>
Link: https://lore.kernel.org/r/20220426123714.2000-1-du@axentia.se
[ johan: amend commit message ]
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/ftdi_sio.c

@@ -1671,7 +1671,7 @@ static ssize_t latency_timer_show(struct device *dev,
 	if (priv->flags & ASYNC_LOW_LATENCY)
 		return sprintf(buf, "1\n");
 	else
-		return sprintf(buf, "%i\n", priv->latency);
+		return sprintf(buf, "%u\n", priv->latency);
 }
 
 /* Write a new value of the latency timer, in units of milliseconds. */