sandbox: Add dummy SATA functions

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

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/block/Makefile

@@ -22,7 +22,7 @@ obj-$(CONFIG_SATA_MV) += sata_mv.o
 obj-$(CONFIG_SATA_SIL3114) += sata_sil3114.o
 obj-$(CONFIG_SATA_SIL) += sata_sil.o
 obj-$(CONFIG_IDE_SIL680) += sil680.o
-obj-$(CONFIG_SANDBOX) += sandbox.o sandbox_scsi.o
+obj-$(CONFIG_SANDBOX) += sandbox.o sandbox_scsi.o sata_sandbox.o
 obj-$(CONFIG_SCSI_SYM53C8XX) += sym53c8xx.o
 obj-$(CONFIG_SYSTEMACE) += systemace.o
 obj-$(CONFIG_BLOCK_CACHE) += blkcache.o

drivers/block/sata_sandbox.c

@@ -0,0 +1,33 @@
+/*
+ * Copyright (C) 2015 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+
+int init_sata(int dev)
+{
+	return 0;
+}
+
+int reset_sata(int dev)
+{
+	return 0;
+}
+
+int scan_sata(int dev)
+{
+	return 0;
+}
+
+ulong sata_read(int dev, ulong blknr, lbaint_t blkcnt, void *buffer)
+{
+	return 0;
+}
+
+ulong sata_write(int dev, ulong blknr, lbaint_t blkcnt, const void *buffer)
+{
+	return 0;
+}