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>
diff --git a/arch/avr32/boards/merisc/setup.c b/arch/avr32/boards/merisc/setup.c
index 58acdb4..20b300c 100644
--- a/arch/avr32/boards/merisc/setup.c
+++ b/arch/avr32/boards/merisc/setup.c
@@ -231,9 +231,9 @@
 
 void __init setup_board(void)
 {
-	at32_map_usart(0, 0);
-	at32_map_usart(1, 1);
-	at32_map_usart(3, 3);
+	at32_map_usart(0, 0, 0);
+	at32_map_usart(1, 1, 0);
+	at32_map_usart(3, 3, 0);
 	at32_setup_serial_console(1);
 }
 
@@ -248,7 +248,7 @@
 	at32_reserve_pin(GPIO_PIOE_BASE, ATMEL_EBI_PE_DATA_ALL | (1 << 26));
 
 	if (merisc_board_id >= 1)
-		at32_map_usart(2, 2);
+		at32_map_usart(2, 2, 0);
 
 	at32_add_device_usart(0);
 	at32_add_device_usart(1);