RDMA/mlx5: Fix UMR cleanup on error flow of driver init

The cited commit removed from the cleanup flow of umr the checks
if the resources were created. This could lead to null-ptr-deref
in case that we had failure in mlx5_ib_stage_ib_reg_init stage.

Fix it by adding new state to the umr that can say if the resources
were created or not and check it in the umr cleanup flow before
destroying the resources.

Fixes: 04876c12

 ("RDMA/mlx5: Move init and cleanup of UMR to umr.c")
Reviewed-by: Michael Guralnik <michaelgur@nvidia.com>
Signed-off-by: Maor Gottlieb <maorg@nvidia.com>
Link: https://lore.kernel.org/r/4cfa61386cf202e9ce330e8d228ce3b25a36326e.1661763459.git.leonro@nvidia.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>