drm/amdkfd: Fix criu_restore_bo error handling

Clang static analysis reports this problem
kfd_chardev.c:2327:2: warning: 1st function call argument
  is an uninitialized value
  kvfree(bo_privs);
  ^~~~~~~~~~~~~~~~

Make sure bo_buckets and bo_privs are initialized so freeing them in the
error handling code path will never result in undefined behaviour.

Fixes: 73fa13b6 ("drm/amdkfd: CRIU Implement KFD restore ioctl")
Reported-by: Tom Rix <trix@redhat.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Rajneesh Bhardwaj <rajneesh.bhardwaj@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>