net/mlx5e: Again mutually exclude RX-FCS and RX-port-timestamp

[ Upstream commit da6192ca ]

Commit 1e662209 ("net/mlx5e: Update rx ring hw mtu upon each rx-fcs
flag change") seems to have accidentally inverted the logic added in
commit 0bc73ad4 ("net/mlx5e: Mutually exclude RX-FCS and
RX-port-timestamp").

The impact of this is a little unclear since it seems the FCS scattered
with RX-FCS is (usually?) correct regardless.

Fixes: 1e662209

 ("net/mlx5e: Update rx ring hw mtu upon each rx-fcs flag change")
Tested-by: Charlotte Tan <charlotte@extrahop.com>
Reviewed-by: Charlotte Tan <charlotte@extrahop.com>
Cc: Adham Faris <afaris@nvidia.com>
Cc: Aya Levin <ayal@nvidia.com>
Cc: Tariq Toukan <tariqt@nvidia.com>
Cc: Moshe Shemesh <moshe@nvidia.com>
Cc: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Will Mortensen <will@extrahop.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://lore.kernel.org/r/20231006053706.514618-1-will@extrahop.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>