drivers: base: test: Add missing MODULE_* macros to root device tests

Commit 06188bc8 ("drivers: base: Add basic devm tests for root
devices") introduced a new set of tests for root devices that could be
compiled as a module, but didn't have the usual module macros.

Make sure they're there.

Fixes: 06188bc8

 ("drivers: base: Add basic devm tests for root devices")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20230816073019.1446155-2-mripard@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>