dm: sandbox: Switch over to using the new host uclass

Update the sandbox implementation to use UCLASS_HOST and adjust all
the pieces to continue to work:

- Update the 'host' command to use the new API
- Replace various uses of UCLASS_ROOT with UCLASS_HOST
- Disable test_eficonfig since it doesn't work (this should have a unit
  test to allow this to be debugged)
- Update the blk test to use the new API
- Drop the old header file

Unfortunately it does not seem to be possible to split this change up
further.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/efi_loader/efi_disk.c b/lib/efi_loader/efi_disk.c
index a50a46c..7ea0334 100644
--- a/lib/efi_loader/efi_disk.c
+++ b/lib/efi_loader/efi_disk.c
@@ -555,7 +555,7 @@
 		if (ret == EFI_NOT_READY)
 			log_notice("Disk %s not ready\n", dev->name);
 		else
-			log_err("Adding disk for %s failed\n", dev->name);
+			log_err("Adding disk for %s failed (err=%ld/%#lx)\n", dev->name, ret, ret);
 
 		return -1;
 	}