sandbox: block driver using host file/device as backing store

Provide a way to use any host file or device as a block device in U-Boot.
This can be used to provide filesystem access within U-Boot to an ext2
image file on the host, for example.

The support is plumbed into the filesystem and partition interfaces.

We don't want to print a message in the driver every time we find a missing
device. Pass the information back to the caller where a message can be printed
if desired.

Signed-off-by: Henrik Nordström <henrik@henriknordstrom.net>
Signed-off-by: Simon Glass <sjg@chromium.org>
- Removed change to part.c get_device_and_partition()

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/disk/part.c b/disk/part.c
index d2e34cf..6941033 100644
--- a/disk/part.c
+++ b/disk/part.c
@@ -43,6 +43,9 @@
 #if defined(CONFIG_SYSTEMACE)
 	{ .name = "ace", .get_dev = systemace_get_dev, },
 #endif
+#if defined(CONFIG_SANDBOX)
+	{ .name = "host", .get_dev = host_get_dev, },
+#endif
 	{ },
 };
 
@@ -286,6 +289,9 @@
 	case IF_TYPE_MMC:
 		puts ("MMC");
 		break;
+	case IF_TYPE_HOST:
+		puts("HOST");
+		break;
 	default:
 		puts ("UNKNOWN");
 		break;