x86: baytrail: Fix boot hang with a debug build

It was observed that when -DDEBUG is used to generate a debug build,
U-Boot does not boot on MinnowMax board. A workaround is to disable
CONFIG_DEBUG_UART. The real issue is that in order to have the debug
uart to work, BayTrail SoC needs to be configured so that its internal
uart is available to be used as the debug uart.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/x86/cpu/baytrail/Kconfig

@@ -17,4 +17,8 @@ config INTERNAL_UART
 	  reason, it is recommended that the UART port be used for
 	  debug purposes only, eg: U-Boot console.
 
+config DEBUG_UART
+	bool
+	select DEBUG_UART_BOARD_INIT
+
 endif

arch/x86/cpu/baytrail/early_uart.c

@@ -80,3 +80,8 @@ int setup_internal_uart(int enable)
 
 	return 0;
 }
+
+void board_debug_uart_init(void)
+{
+	setup_internal_uart(1);
+}