serial: ar933x_uart: Fix off-by-one for checking valid alias id

Current code uses the alias id as array subscript of ar933x_console_ports.
So the valid id is 0 ... CONFIG_SERIAL_AR933X_NR_UARTS - 1.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/serial/ar933x_uart.c b/drivers/tty/serial/ar933x_uart.c
index 77fc9fa..1519d2c 100644
--- a/drivers/tty/serial/ar933x_uart.c
+++ b/drivers/tty/serial/ar933x_uart.c
@@ -649,7 +649,7 @@
 			id = 0;
 	}
 
-	if (id > CONFIG_SERIAL_AR933X_NR_UARTS)
+	if (id >= CONFIG_SERIAL_AR933X_NR_UARTS)
 		return -EINVAL;
 
 	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);