drm/ttm/tests: Fix a warning in ttm_bo_unreserve_bulk

drm/ttm/tests: Fix a warning in ttm_bo_unreserve_bulk

BOs in a bulk move have to share the same reservation object. That is
not the case in the ttm_bo_unreserve_bulk subtest. Update
ttm_bo_kunit_init() helper to accept dma_resv object so we can define
buffer objects that share the same resv. Update calls to that helper
accordingly.

Fixes: 995279d280d1 ("drm/ttm/tests: Add tests for ttm_bo functions")
Suggested-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Karolina Stolarek <karolina.stolarek@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c5bd2df114781b4eb5c1e8295b2ae4ac2c30a179.1718192625.git.karolina.stolarek@intel.com