net/mlx5e: Fix ethtool pause support and advertise reporting

Pause bit should set when RX pause is on, not TX pause.
Also, setting Asym_Pause is incorrect, and should be turned off.

Fixes: 665bc539 ("net/mlx5e: Use new ethtool get/set link ksettings API")
Signed-off-by: Gal Pressman <galp@mellanox.com>
Cc: kernel-team@fb.com
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>