board: at91sam9260ek/9g20ek: Enable early debug UART

Enable the early debug UART to debug problems when an ICE or other
debug mechanism is not available.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/configs/at91sam9g20ek_dataflash_cs1_defconfig b/configs/at91sam9g20ek_dataflash_cs1_defconfig
index 18e2a17..1826e6c 100644
--- a/configs/at91sam9g20ek_dataflash_cs1_defconfig
+++ b/configs/at91sam9g20ek_dataflash_cs1_defconfig
@@ -31,6 +31,12 @@
 CONFIG_PINCTRL=y
 CONFIG_PINCTRL_AT91=y
 CONFIG_DM_SERIAL=y
+CONFIG_DEBUG_UART=y
+CONFIG_DEBUG_UART_ATMEL=y
+CONFIG_DEBUG_UART_BASE=0xfffff200
+CONFIG_DEBUG_UART_CLOCK=132000000
+CONFIG_DEBUG_UART_BOARD_INIT=y
+CONFIG_DEBUG_UART_ANNOUNCE=y
 CONFIG_ATMEL_USART=y
 CONFIG_USB=y
 CONFIG_USB_STORAGE=y