CVE-2026-98498: net/mlx5: Fix rev_entry reference leak in mlx5_tc_ct_shared_counter_get()

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Fix reventry reference leak in mlx5tcctsharedcounterget()

When the reverse entry is found but its counter is already being released, refcountincnotzero() fails and the reference taken by mlx5tcctentryget() is never dropped before falling through to createcounter. Drop it so the reverse entry is not kept alive forever by a shared counter lookup that did not use it.