net/mlx5: Take TIR destruction out of the TIR list lock

res->td.list_lock protects the list of TIRs. There is no point to call
mlx5_core_destroy_tir() and invoke a firmware command under this lock.
This commit moves this call outside of the lock and puts it after
deleting the TIR from the list to ensure that TIRs are always alive
while in the list.

Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>