[POWERPC] 52xx: Fix mpc52xx_uart_of_assign to use correct index

Use idx as index into mpc52xx_uart_nodes instead of i
Signed-off-by: John Rigby <jrigby@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>

drivers/serial/mpc52xx_uart.c

@@ -1051,7 +1051,7 @@ mpc52xx_uart_of_assign(struct device_node *np, int idx)
 	/* If the slot is already occupied, then swap slots */
 	if (mpc52xx_uart_nodes[idx] && (free_idx != -1))
 		mpc52xx_uart_nodes[free_idx] = mpc52xx_uart_nodes[idx];
-	mpc52xx_uart_nodes[i] = np;
+	mpc52xx_uart_nodes[idx] = np;
 }
 
 static void