regex/mlx5: remove unnecessary initializations

regex/mlx5: remove unnecessary initializations

The rxp_poll_csr_for_value function defines a variable named ret. It is
the return value of the function, and it is updated to 0 by default
later in the function.
Similarly the rxp_init_rtru function also defines a variable named ret.
The function assigns into it return values from functions during the
function.

In both functions they initialize the ret variable when defining it.
however, in both cases they do not use any ret variable before assigning
into them different values, so the initializations are unnecessary.

Clean the aforementioned unnecessary initializations.

Fixes: e3dbbf718ebc ("regex/mlx5: support configuration")
Fixes: b34d816363b5 ("regex/mlx5: support rules import")
Cc: stable@dpdk.org
Signed-off-by: Michael Baum <michaelba@nvidia.com>
Acked-by: Ori Kam <orika@nvidia.com>