sandbox: Add host filesystem

This allows reading of files from the host filesystem in sandbox.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@ti.com>
diff --git a/fs/fs.c b/fs/fs.c
index 95c882e..6f5063c 100644
--- a/fs/fs.c
+++ b/fs/fs.c
@@ -20,6 +20,7 @@
 #include <ext4fs.h>
 #include <fat.h>
 #include <fs.h>
+#include <sandboxfs.h>
 #include <asm/io.h>
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -78,6 +79,15 @@
 		.read = ext4_read_file,
 	},
 #endif
+#ifdef CONFIG_SANDBOX
+	{
+		.fstype = FS_TYPE_SANDBOX,
+		.probe = sandbox_fs_set_blk_dev,
+		.close = sandbox_fs_close,
+		.ls = sandbox_fs_ls,
+		.read = fs_read_sandbox,
+	},
+#endif
 	{
 		.fstype = FS_TYPE_ANY,
 		.probe = fs_probe_unsupported,