rx_ppp and tx_ppp can be set between 0 and 255, so don't clamp to 1.

Fixes: 6e8814ce ("net/mlx4_en: Fix mixed PFC and Global pause user control requests")
Signed-off-by: Tarick Bedeir <tarick@google.com>
Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>