scsi: core: Really include kunit tests with SCSI_LIB_KUNIT_TEST

Commit 25a1f7a0

 ("scsi: core: Add kunit tests for
scsi_check_passthrough()") adds the config SCSI_LIB_KUNIT_TEST and
corresponding tests. Due to naming confusion, the actual tests would only
be included when the non-existing config SCSI_KUNIT_TEST is enabled (note
this missing 'LIB' in the config name). So, they are basically dead right
now.

Adjust the name to actual existing config.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20240207145603.15680-1-lukas.bulwahn@gmail.com
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>