avr32: add RTS/CTS/CLK pin selection for the USARTs

Adds extra parameter to AT32 at32_map_usart(), so as to reserve
RTS/CTS/CLK pins.

All boards under arch/avr32/boards have been updated (trivial change), but
not all have been tested.

Signed-off-by: Peter Ma <pma@mediamatech.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>

arch/avr32/boards/favr-32/setup.c

@@ -250,7 +250,7 @@ static void __init favr32_setup_atmel_pwm_bl(void)
 
 void __init setup_board(void)
 {
-	at32_map_usart(3, 0);	/* USART 3 => /dev/ttyS0 */
+	at32_map_usart(3, 0, 0);	/* USART 3 => /dev/ttyS0 */
 	at32_setup_serial_console(0);
 }