kunit: Fix some comments which were mistakenly kerneldoc

kunit: Fix some comments which were mistakenly kerneldoc

The KUnit device helpers are documented with kerneldoc in their header
file, but also have short comments over their implementation. These were
mistakenly formatted as kerneldoc comments, even though they're not
valid kerneldoc. It shouldn't cause any serious problems -- this file
isn't included in the docs -- but it could be confusing, and causes
warnings.

Remove the extra '*' so that these aren't treated as kerneldoc.

Fixes: d03c720e03bd ("kunit: Add APIs for managing devices")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202312181920.H4EPAH20-lkp@intel.com/
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>