net/mlx5: Add RoCE RX ICRC encapsulated counter

Add capability bit in PCAM register and RoCE ICRC error counter
to PPCNT register.

Signed-off-by: Talat Batheesh <talatb@mellanox.com>
Reviewed-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>