test: sandbox: fix link error with do_ut_bloblist if BLOBLIST=n

Having CONFIG_OF_EMBED=y && CONFIG_BLOBLIST=n leads to the link
error:
```
ld: /tmp/ccwtRVty.ltrans28.ltrans.o:(.data.rel+0x4b0): undefined \
                                         reference to `do_ut_bloblist'
```

Fixes: 6ea5df39e8d ("test: Only enable bloblist test when supported")
Signed-off-by: Evgeny Bachinin <EABachinin@salutedevices.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
1 file changed