sandbox: Avoid requiring CMDLINE

Add some dependencies on features that we had been selecting so that we
can still disable CMDLINE.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Rini <trini@konsulko.com>
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Changes in v4:
- Reword the commit slightly (Tom)
- Rework overall to select if CMDLINE

Changes in v3:
- Reorder the Kconfig options a little