sandbox: Add dummy SCSI functions

Add some functions needed by the SCSI code. This allows it to be compiled
for sandbox, thus increasing build coverage.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/block/sandbox_scsi.c b/drivers/block/sandbox_scsi.c
new file mode 100644
index 0000000..ad961bd
--- /dev/null
+++ b/drivers/block/sandbox_scsi.c
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ *
+ * This file contains dummy implementations of SCSI functions requried so
+ * that CONFIG_SCSI can be enabled for sandbox.
+ */
+
+#include <common.h>
+#include <scsi.h>
+
+void scsi_bus_reset(void)
+{
+}
+
+void scsi_init(void)
+{
+}
+
+int scsi_exec(ccb *pccb)
+{
+	return 0;
+}
+
+void scsi_print_error(ccb *pccb)
+{
+}