drm/xe: Fix error paths of __xe_bo_create_locked

ttm_bo_init_reserved() calls the destroy() callback if it fails.

Because of this, __xe_bo_create_locked is required to be responsible
for freeing the bo even when it's passed in as argument.

Additionally, if the placement check fails, the bo was kept alive.
Fix it too.

Reported-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>