sandbox: Enable console recording and silent console

Allow console recording so that tests can use it. Also allow the console
output to be suppressed, to reduce test output 'noise'.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/sandbox.h b/include/configs/sandbox.h
index b0fe501..fb1bfb7 100644
--- a/include/configs/sandbox.h
+++ b/include/configs/sandbox.h
@@ -65,6 +65,7 @@
 #define CONFIG_SYS_HUSH_PARSER
 #define CONFIG_SYS_LONGHELP			/* #undef to save memory */
 #define CONFIG_SYS_CBSIZE		1024	/* Console I/O Buffer Size */
+#define CONFIG_SILENT_CONSOLE
 
 /* Print Buffer Size */
 #define CONFIG_SYS_PBSIZE (CONFIG_SYS_CBSIZE + sizeof(CONFIG_SYS_PROMPT) + 16)