net/mlx5e: Declare mlx5e_tx_reporter_recover_from_ctx as static

Function mlx5e_tx_reporter_recover_from_ctx is only used within mlx5e tx
reporter, move it to be statically declared in en/reporter_tx.c.

Fixes: de8650a8 ("net/mlx5e: Add tx reporter support")
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reported-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>