board: sama5d2_xplained: Enable an early debug UART

Enable an 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>
Reviewed-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/configs/sama5d2_xplained_mmc_defconfig b/configs/sama5d2_xplained_mmc_defconfig
index 08ecea6..8a786f1 100644
--- a/configs/sama5d2_xplained_mmc_defconfig
+++ b/configs/sama5d2_xplained_mmc_defconfig
@@ -52,6 +52,12 @@
 CONFIG_SPI_FLASH_ATMEL=y
 CONFIG_PINCTRL=y
 CONFIG_PINCTRL_AT91PIO4=y
+CONFIG_DEBUG_UART=y
+CONFIG_DEBUG_UART_ATMEL=y
+CONFIG_DEBUG_UART_BASE=0xf8020000
+CONFIG_DEBUG_UART_CLOCK=0
+CONFIG_DEBUG_UART_BOARD_INIT=y
+CONFIG_DEBUG_UART_ANNOUNCE=y
 CONFIG_ATMEL_USART=y
 CONFIG_DM_SPI=y
 CONFIG_ATMEL_SPI=y