sandbox: Enable more console options

Enable the pre-console buffer, displaying the model and post-relocation
console announce on sandbox. Also add a model name to the device tree.
This allows testing of these features.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Tested-by: Stephen Warren <swarren@nvidia.com>
diff --git a/common/Kconfig b/common/Kconfig
index 086b676..361346b 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -488,7 +488,7 @@
 
 config DISPLAY_BOARDINFO
 	bool "Display information about the board during start up"
-	default y if ARM || M68K || MIPS || PPC || XTENSA
+	default y if ARM || M68K || MIPS || PPC || SANDBOX || XTENSA
 	help
 	  Display information about the board that U-Boot is running on
 	  when U-Boot starts up. The board function checkboard() is called