net/mlx5e: Avoid overriding the user provided priority for offloaded tc rules

Just a leftover which was wrongly left there, remove it while spawning
a message to suggest firmware upgrade.

Fixes: bf07aa73 ('net/mlx5e: Support offloading tc priorities and chains for eswitch flows')
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Paul Blakey <paulb@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>